Add more functionality to hardware key rebinding 2/2

this adds a great deal more functionality and customization potential to the
hardware key rebinding including the ability to disable individual keys.

TO DO:  rework the interface to be less of a gross looking clusterfuck

additional actions:
- back key as a rebindable target
- home shortpress rebindability
- navigate back
- navigate home
- kill task
- last app
- IME switcher
- power menu
- toggle navbar

PSCLEANUP: reorder the string-array to preserve the original functions

Change-Id: I46df17bf4bb337ec80d83a827d381b3e44fbc0b9

Conflicts:
	src/com/android/settings/DevelopmentSettings.java