Project restructure

We don't need to separate widget/onscreen from the main module, let's merge them together.

android-app/src/main/res/layout/onscreen_display.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!--
+  ~ Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+  ~ For more information, please, contact se.solovyev@gmail.com
+  ~ or visit http://se.solovyev.org
+  -->
+
+<org.solovyev.android.calculator.AndroidCalculatorDisplayView xmlns:a="http://schemas.android.com/apk/res/android"
+															  a:id="@+id/calculator_display"
+															  style="@style/cpp_onscreen_display_style"
+															  a:padding="@dimen/cpp_display_padding"
+															  a:inputType="textMultiLine"
+															  a:maxLines="3"
+															  a:scrollHorizontally="false"
+															  a:scrollbars="none"/>