Settings: disable lockscreen settings appropriately

Give visual feedback on which features are unavailable
with the new lockscreen style.

Change-Id: I05b905e9a6e48d884943156b2dedc93ceee57bc4
Signed-off-by: Roman Birg <roman@cyngn.com>

Conflicts:
	src/com/android/settings/cyanogenmod/LockscreenInterface.java