Settings : Make proximity opt-in

Change-Id: Idfa64758a3c6d60ca4801f6f7f34f0429f95cbec

Conflicts:
	res/xml/display_settings.xml
	src/com/android/settings/DisplaySettings.java
Slim Pie : rework UI and cleanup
PA PIE : UI rework and fix

- use action bar switch
- remove force ui restart (no longer need)
- fix navbar and gravity logic
- use SlimAction to provide navbar activity to fix possible npe.
Use centralize strings
QuietHours : become first class citizen (1/2)

- add Enabler options for easy trigger
  use quiet_hours_state to store last settings to handle toggle actions.