highlighting in editor + refactor

res/layout-land/main.xml

@@ -15,7 +15,7 @@
 
 		<LinearLayout a:layout_weight="2" a:layout_width="match_parent" a:layout_height="0dp">
 
-			<org.solovyev.android.calculator.CalculatorEditText
+			<org.solovyev.android.calculator.CalculatorEditor
 					a:id="@+id/editText"
 					style="@style/display_style"
 					a:inputType="textMultiLine"

res/layout-port/main.xml

@@ -15,7 +15,7 @@
 
 		<LinearLayout a:layout_weight="2" a:layout_width="match_parent" a:layout_height="0dp">
 
-			<org.solovyev.android.calculator.CalculatorEditText
+			<org.solovyev.android.calculator.CalculatorEditor
 					a:id="@+id/editText"
 					style="@style/display_style"
 					a:inputType="textMultiLine"

res/layout/var_edit.xml

@@ -26,6 +26,7 @@
 		<EditText a:id="@+id/var_edit_name"
 				  a:layout_width="match_parent"
 				  a:layout_height="wrap_content"
+				  a:digits="abcdefghijklmnopqrstuvwxyz1234567890"
 				  a:textSize="20dp">
 		</EditText>
 

res/values/strings.xml

@@ -31,7 +31,7 @@
 	<string name="c_paste">paste</string>
 	<string name="c_vars">vars</string>
 
-	<string name="c_calc_color_display_title">Color expressions</string>
+	<string name="c_calc_color_display_title">Highlight expressions</string>
 	<string name="p_calc_result_precision_title">Precision of result</string>
 	<string name="c_exit">Exit</string>
 	<string name="c_add">Add</string>
@@ -43,7 +43,7 @@
 	<string name="c_var_removal_confirmation">Removal confirmation</string>
 	<string name="c_var_removal_confirmation_question">Do you really want to delete \'%s\' variable?</string>
 	<string name="c_var_name">Name</string>
-	<string name="c_var_value">value</string>
+	<string name="c_var_value">Value</string>
 	<string name="c_var_description">Description</string>
 	<string name="c_var_create_var">Create variable</string>
 	<string name="c_var_edit_var">Edit variable</string>