Settings: Toggle Stylus Pointer Icon

For devices with s-pen, this adds an option to disable
the mouse pointer when using s-pen

Conflicts:
	res/values/custom_strings.xml
	src/com/android/settings/inputmethod/InputMethodAndLanguageSettings.java

Change-Id: I8e752a8c8fd6a276eaf9b6bf20ad89d5ce3459ba