diff --git a/.idea/codeStyleSettings.xml b/.idea/codeStyleSettings.xml
index eee0ba6d..e2779986 100644
--- a/.idea/codeStyleSettings.xml
+++ b/.idea/codeStyleSettings.xml
@@ -46,6 +46,34 @@
         <AndroidXmlCodeStyleSettings>
           <option name="USE_CUSTOM_SETTINGS" value="true" />
         </AndroidXmlCodeStyleSettings>
+        <Objective-C-extensions>
+          <option name="GENERATE_INSTANCE_VARIABLES_FOR_PROPERTIES" value="ASK" />
+          <option name="RELEASE_STYLE" value="IVAR" />
+          <option name="TYPE_QUALIFIERS_PLACEMENT" value="BEFORE" />
+          <file>
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Import" />
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Macro" />
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Typedef" />
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Enum" />
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Constant" />
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Global" />
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Struct" />
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="FunctionPredecl" />
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Function" />
+          </file>
+          <class>
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Property" />
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Synthesize" />
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InitMethod" />
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="StaticMethod" />
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InstanceMethod" />
+            <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="DeallocMethod" />
+          </class>
+          <extensions>
+            <pair source="cpp" header="h" />
+            <pair source="c" header="h" />
+          </extensions>
+        </Objective-C-extensions>
         <XML>
           <option name="XML_LEGACY_SETTINGS_IMPORTED" value="true" />
         </XML>
diff --git a/.idea/gradle.xml b/.idea/gradle.xml
index afa3dedb..5f593ebd 100644
--- a/.idea/gradle.xml
+++ b/.idea/gradle.xml
@@ -4,9 +4,9 @@
     <option name="linkedExternalProjectsSettings">
       <GradleProjectSettings>
         <option name="createEmptyContentRootDirectories" value="true" />
-        <option name="distributionType" value="DEFAULT_WRAPPED" />
+        <option name="distributionType" value="LOCAL" />
         <option name="externalProjectPath" value="$PROJECT_DIR$" />
-        <option name="gradleHome" value="/opt/gradle" />
+        <option name="gradleHome" value="$APPLICATION_HOME_DIR$/gradle/gradle-2.4" />
         <option name="gradleJvm" value="1.7" />
         <option name="modules">
           <set>
diff --git a/.idea/runConfigurations.xml b/.idea/runConfigurations.xml
new file mode 100644
index 00000000..7f68460d
--- /dev/null
+++ b/.idea/runConfigurations.xml
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RunConfigurationProducerService">
+    <option name="ignoredProducers">
+      <set>
+        <option value="org.jetbrains.plugins.gradle.execution.test.runner.AllInPackageGradleConfigurationProducer" />
+        <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestClassGradleConfigurationProducer" />
+        <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestMethodGradleConfigurationProducer" />
+      </set>
+    </option>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/runConfigurations/Run.xml b/.idea/runConfigurations/Run.xml
index 86690768..ebff215a 100644
--- a/.idea/runConfigurations/Run.xml
+++ b/.idea/runConfigurations/Run.xml
@@ -2,6 +2,7 @@
   <configuration default="false" name="Run" type="AndroidRunConfigurationType" factoryName="Android Application">
     <module name="android-app" />
     <option name="ACTIVITY_CLASS" value="" />
+    <option name="ACTIVITY_EXTRA_FLAGS" value="" />
     <option name="MODE" value="default_activity" />
     <option name="DEPLOY" value="true" />
     <option name="ARTIFACT_NAME" value="" />
@@ -16,11 +17,17 @@
     <option name="NETWORK_LATENCY" value="none" />
     <option name="CLEAR_LOGCAT" value="false" />
     <option name="SHOW_LOGCAT_AUTOMATICALLY" value="true" />
-    <option name="FILTER_LOGCAT_AUTOMATICALLY" value="true" />
-    <option name="SELECTED_MATRIX_CONFIGURATION_ID" value="0" />
-    <option name="SELECTED_CLOUD_PROJECT_ID" value="" />
-    <option name="IS_VALID_CLOUD_SELECTION" value="false" />
-    <option name="INVALID_CLOUD_SELECTION_ERROR" value="" />
+    <option name="SKIP_NOOP_APK_INSTALLATIONS" value="true" />
+    <option name="FORCE_STOP_RUNNING_APP" value="true" />
+    <option name="SELECTED_CLOUD_MATRIX_CONFIGURATION_ID" value="0" />
+    <option name="SELECTED_CLOUD_MATRIX_PROJECT_ID" value="" />
+    <option name="SELECTED_CLOUD_DEVICE_CONFIGURATION_ID" value="0" />
+    <option name="SELECTED_CLOUD_DEVICE_PROJECT_ID" value="" />
+    <option name="IS_VALID_CLOUD_MATRIX_SELECTION" value="false" />
+    <option name="INVALID_CLOUD_MATRIX_SELECTION_ERROR" value="" />
+    <option name="IS_VALID_CLOUD_DEVICE_SELECTION" value="false" />
+    <option name="INVALID_CLOUD_DEVICE_SELECTION_ERROR" value="" />
+    <option name="CLOUD_DEVICE_SERIAL_NUMBER" value="" />
     <RunnerSettings RunnerId="AndroidDebugRunner" />
     <ConfigurationWrapper RunnerId="AndroidDebugRunner" />
     <method />
diff --git a/android-app-tests/android-app-tests.iml b/android-app-tests/android-app-tests.iml
index 62b50867..35cfdfec 100644
--- a/android-app-tests/android-app-tests.iml
+++ b/android-app-tests/android-app-tests.iml
@@ -13,7 +13,7 @@
       </configuration>
     </facet>
   </component>
-  <component name="NewModuleRootManager" inherit-compiler-output="false">
+  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_7" inherit-compiler-output="false">
     <output url="file://$MODULE_DIR$/build/classes/main" />
     <output-test url="file://$MODULE_DIR$/build/classes/test" />
     <exclude-output />
@@ -27,7 +27,6 @@
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
-    <orderEntry type="module" module-name="android-app" exported="" />
     <orderEntry type="library" exported="" scope="TEST" name="junit-4.11" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="robolectric-2.3" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="mockito-all-1.9.5" level="project" />
@@ -74,16 +73,15 @@
     <orderEntry type="library" exported="" scope="TEST" name="xercesMinimal-1.9.6.2" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="nekohtml-1.9.6.2" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="support-annotations-22.1.1" level="project" />
-    <orderEntry type="library" exported="" scope="TEST" name="jscl-1.0.11" level="project" />
-    <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="simple-xml-2.6.1" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
+    <orderEntry type="library" exported="" scope="TEST" name="core" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="commons-cli-1.2" level="project" />
-    <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="annotations-2.0.1" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
-    <orderEntry type="library" exported="" scope="TEST" name="core" level="project" />
+    <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
+    <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="stax-1.2.0" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
@@ -92,26 +90,25 @@
     <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="guava-11.0.2" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
+    <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="library-2.4.0" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="common-text-1.0.7" level="project" />
-    <orderEntry type="library" exported="" scope="TEST" name="internal_impl-22.2.0" level="project" />
-    <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
-    <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="acra-4.5.0" level="project" />
-    <orderEntry type="library" exported="" scope="TEST" name="support-annotations-22.2.0" level="project" />
+    <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="leakcanary-analyzer-1.3.1" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="common-core-1.0.7" level="project" />
+    <orderEntry type="library" exported="" scope="TEST" name="_home_serso_projects_java_serso_android_calculatorpp_android_app_build_intermediates_exploded_aar_com_android_support_support_v4_23_1_0_jars_classes_jar" level="project" />
+    <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="common-security-1.0.7" level="project" />
-    <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
+    <orderEntry type="library" exported="" scope="TEST" name="_home_serso_projects_java_serso_android_calculatorpp_android_app_build_intermediates_exploded_aar_com_android_support_appcompat_v7_23_1_0_jars_classes_jar" level="project" />
+    <orderEntry type="library" exported="" scope="TEST" name="jscl-1.0.11" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="leakcanary-watcher-1.3.1" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="haha-1.3" level="project" />
+    <orderEntry type="library" exported="" scope="TEST" name="support-annotations-23.1.0" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
-    <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
-    <orderEntry type="library" exported="" scope="TEST" name="classes" level="project" />
-    <orderEntry type="library" exported="" scope="TEST" name="_home_serso_projects_java_android_calculatorpp_android_app_build_intermediates_classes_debug" level="project" />
-    <orderEntry type="library" exported="" scope="TEST" name="_home_serso_projects_java_android_calculatorpp_android_app_build_intermediates_dependency_cache_debug" level="project" />
+    <orderEntry type="library" exported="" scope="TEST" name="_home_serso_projects_java_serso_android_calculatorpp_android_app_build_intermediates_classes_debug" level="project" />
+    <orderEntry type="library" exported="" scope="TEST" name="_home_serso_projects_java_serso_android_calculatorpp_android_app_build_intermediates_dependency_cache_debug" level="project" />
     <orderEntry type="library" exported="" scope="TEST" name="android" level="project" />
-    <orderEntry type="library" exported="" name="android-app-tests.android-app-tests" level="project" />
   </component>
 </module>
\ No newline at end of file
diff --git a/android-app/android-app.iml b/android-app/android-app.iml
index 1135af02..bc2e2ca8 100644
--- a/android-app/android-app.iml
+++ b/android-app/android-app.iml
@@ -12,10 +12,12 @@
         <option name="SELECTED_TEST_ARTIFACT" value="_android_test_" />
         <option name="ASSEMBLE_TASK_NAME" value="assembleDebug" />
         <option name="COMPILE_JAVA_TASK_NAME" value="compileDebugSources" />
-        <option name="SOURCE_GEN_TASK_NAME" value="generateDebugSources" />
         <option name="ASSEMBLE_TEST_TASK_NAME" value="assembleDebugAndroidTest" />
         <option name="COMPILE_JAVA_TEST_TASK_NAME" value="compileDebugAndroidTestSources" />
-        <option name="TEST_SOURCE_GEN_TASK_NAME" value="generateDebugAndroidTestSources" />
+        <afterSyncTasks>
+          <task>generateDebugAndroidTestSources</task>
+          <task>generateDebugSources</task>
+        </afterSyncTasks>
         <option name="ALLOW_USER_CONFIGURATION" value="false" />
         <option name="MANIFEST_FILE_RELATIVE_PATH" value="/src/main/AndroidManifest.xml" />
         <option name="RES_FOLDER_RELATIVE_PATH" value="/src/main/res" />
@@ -24,7 +26,7 @@
       </configuration>
     </facet>
   </component>
-  <component name="NewModuleRootManager" inherit-compiler-output="false">
+  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_7" inherit-compiler-output="false">
     <output url="file://$MODULE_DIR$/build/intermediates/classes/debug" />
     <output-test url="file://$MODULE_DIR$/build/intermediates/classes/androidTest/debug" />
     <exclude-output />
@@ -34,13 +36,13 @@
       <sourceFolder url="file://$MODULE_DIR$/build/generated/source/buildConfig/debug" isTestSource="false" generated="true" />
       <sourceFolder url="file://$MODULE_DIR$/build/generated/source/rs/debug" isTestSource="false" generated="true" />
       <sourceFolder url="file://$MODULE_DIR$/build/generated/res/rs/debug" type="java-resource" />
-      <sourceFolder url="file://$MODULE_DIR$/build/generated/res/generated/debug" type="java-resource" />
+      <sourceFolder url="file://$MODULE_DIR$/build/generated/res/resValues/debug" type="java-resource" />
       <sourceFolder url="file://$MODULE_DIR$/build/generated/source/r/androidTest/debug" isTestSource="true" generated="true" />
       <sourceFolder url="file://$MODULE_DIR$/build/generated/source/aidl/androidTest/debug" isTestSource="true" generated="true" />
       <sourceFolder url="file://$MODULE_DIR$/build/generated/source/buildConfig/androidTest/debug" isTestSource="true" generated="true" />
       <sourceFolder url="file://$MODULE_DIR$/build/generated/source/rs/androidTest/debug" isTestSource="true" generated="true" />
       <sourceFolder url="file://$MODULE_DIR$/build/generated/res/rs/androidTest/debug" type="java-test-resource" />
-      <sourceFolder url="file://$MODULE_DIR$/build/generated/res/generated/androidTest/debug" type="java-test-resource" />
+      <sourceFolder url="file://$MODULE_DIR$/build/generated/res/resValues/androidTest/debug" type="java-test-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/res" type="java-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/resources" type="java-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/assets" type="java-resource" />
@@ -69,9 +71,9 @@
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/dependency-cache" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/dex" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/dex-cache" />
-      <excludeFolder url="file://$MODULE_DIR$/build/intermediates/exploded-aar/com.android.support/appcompat-v7/22.2.0/jars" />
+      <excludeFolder url="file://$MODULE_DIR$/build/intermediates/exploded-aar/com.android.support/appcompat-v7/23.1.0/jars" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/exploded-aar/com.android.support/recyclerview-v7/21.0.0/jars" />
-      <excludeFolder url="file://$MODULE_DIR$/build/intermediates/exploded-aar/com.android.support/support-v4/22.2.0/jars" />
+      <excludeFolder url="file://$MODULE_DIR$/build/intermediates/exploded-aar/com.android.support/support-v4/23.1.0/jars" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/exploded-aar/com.google.android.gms/play-services-ads/7.5.0/jars" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/exploded-aar/com.google.android.gms/play-services-analytics/7.5.0/jars" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/exploded-aar/com.google.android.gms/play-services-base/7.5.0/jars" />
@@ -97,12 +99,10 @@
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/res" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/rs" />
       <excludeFolder url="file://$MODULE_DIR$/build/intermediates/symbols" />
-      <excludeFolder url="file://$MODULE_DIR$/build/libs" />
       <excludeFolder url="file://$MODULE_DIR$/build/outputs" />
-      <excludeFolder url="file://$MODULE_DIR$/build/poms" />
       <excludeFolder url="file://$MODULE_DIR$/build/tmp" />
     </content>
-    <orderEntry type="jdk" jdkName="Android API 22 Platform" jdkType="Android SDK" />
+    <orderEntry type="jdk" jdkName="Android API 23 Platform" jdkType="Android SDK" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" exported="" name="play-services-base-7.5.0" level="project" />
     <orderEntry type="library" exported="" name="acra-4.5.0" level="project" />
@@ -112,14 +112,15 @@
     <orderEntry type="library" exported="" name="common-text-1.0.7" level="project" />
     <orderEntry type="library" exported="" name="android-common-views-1.1.18" level="project" />
     <orderEntry type="library" exported="" name="stax-1.2.0" level="project" />
+    <orderEntry type="library" exported="" name="appcompat-v7-23.1.0" level="project" />
     <orderEntry type="library" exported="" name="jscl-1.0.11" level="project" />
     <orderEntry type="library" exported="" name="library-2.4.0" level="project" />
     <orderEntry type="library" exported="" name="material-0.1.3" level="project" />
     <orderEntry type="library" exported="" name="android-common-menus-1.1.18" level="project" />
     <orderEntry type="library" exported="" name="leakcanary-analyzer-1.3.1" level="project" />
     <orderEntry type="library" exported="" name="recyclerview-v7-21.0.0" level="project" />
+    <orderEntry type="library" exported="" name="support-annotations-23.1.0" level="project" />
     <orderEntry type="library" exported="" name="play-services-analytics-7.5.0" level="project" />
-    <orderEntry type="library" exported="" name="support-annotations-22.2.0" level="project" />
     <orderEntry type="library" exported="" name="common-security-1.0.7" level="project" />
     <orderEntry type="library" exported="" name="leakcanary-watcher-1.3.1" level="project" />
     <orderEntry type="library" exported="" name="android-common-core-1.1.18" level="project" />
@@ -129,13 +130,12 @@
     <orderEntry type="library" exported="" name="floatingactionbutton-1.1.0" level="project" />
     <orderEntry type="library" exported="" name="checkout-0.7.2" level="project" />
     <orderEntry type="library" exported="" name="android-common-preferences-1.1.18" level="project" />
-    <orderEntry type="library" exported="" name="support-v4-22.2.0" level="project" />
     <orderEntry type="library" exported="" name="android-common-lists-1.1.18" level="project" />
     <orderEntry type="library" exported="" name="guava-11.0.2" level="project" />
     <orderEntry type="library" exported="" name="commons-cli-1.2" level="project" />
-    <orderEntry type="library" exported="" name="appcompat-v7-22.2.0" level="project" />
     <orderEntry type="library" exported="" name="leakcanary-android-1.3.1" level="project" />
     <orderEntry type="library" exported="" name="simple-xml-2.6.1" level="project" />
+    <orderEntry type="library" exported="" name="support-v4-23.1.0" level="project" />
     <orderEntry type="library" exported="" name="play-services-ads-7.5.0" level="project" />
     <orderEntry type="module" module-name="core" exported="" />
   </component>
diff --git a/android-app/build.gradle b/android-app/build.gradle
index 07cf4c32..59303454 100644
--- a/android-app/build.gradle
+++ b/android-app/build.gradle
@@ -56,8 +56,8 @@ dependencies {
     compile 'org.solovyev:common-core:1.0.7'
     compile 'org.solovyev:common-text:1.0.7'
     compile 'org.solovyev:common-security:1.0.7'
-    compile 'com.android.support:support-v4:22.2.0'
-    compile 'com.android.support:appcompat-v7:22.2.0'
+    compile 'com.android.support:support-v4:23.1.0'
+    compile 'com.android.support:appcompat-v7:23.1.0'
     compile('ch.acra:acra:4.5.0') {
         exclude group: 'org.json'
     }
diff --git a/build.gradle b/build.gradle
index d03f330b..f769e60b 100644
--- a/build.gradle
+++ b/build.gradle
@@ -7,11 +7,11 @@ public String version_name() {
 }
 
 public int android_sdk_version() {
-  return 22
+  return 23
 }
 
 public String android_build_tools_version() {
-  return '22.0.1'
+  return '23.0.1'
 }
 
 public String android_min_sdk_version() {
@@ -24,7 +24,7 @@ buildscript {
     mavenCentral()
   }
   dependencies {
-    classpath 'com.android.tools.build:gradle:1.2.3'
+    classpath 'com.android.tools.build:gradle:1.3.0'
   }
 }
 
diff --git a/calculatorpp.iml b/calculatorpp.iml
index 1f90f96a..ee0248d1 100644
--- a/calculatorpp.iml
+++ b/calculatorpp.iml
@@ -8,7 +8,7 @@
       </configuration>
     </facet>
   </component>
-  <component name="NewModuleRootManager" inherit-compiler-output="true">
+  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_7" inherit-compiler-output="true">
     <exclude-output />
     <content url="file://$MODULE_DIR$">
       <excludeFolder url="file://$MODULE_DIR$/.gradle" />
diff --git a/core/core.iml b/core/core.iml
index 64170b79..64b4429a 100644
--- a/core/core.iml
+++ b/core/core.iml
@@ -13,7 +13,7 @@
       </configuration>
     </facet>
   </component>
-  <component name="NewModuleRootManager" inherit-compiler-output="false">
+  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_7" inherit-compiler-output="false">
     <output url="file://$MODULE_DIR$/build/classes/main" />
     <output-test url="file://$MODULE_DIR$/build/classes/test" />
     <exclude-output />