Port "immersive mode"

Credits to Chameleon OS

Conflicts:
	res/values/purity_arrays.xml
	res/values/purity_strings.xml
	res/xml/power_menu_settings.xml
	src/com/android/settings/purity/PowerMenu.java
Revert "Port "immersive mode""

This reverts commit 3d3cc488dcab0f355e84e2b6475178e6cfa0829f.