Fix Derp
settings: use centralized strings

strings like default, enabled, disabled are common
and often used. Use always the same string due that
it is easier to maintain especially for our translators

statusbar settings shows now enabled/disabled for clock
options

Change-Id: I56399948cc09c0ddd922b884573ed36375772147

Conflicts:
	res/xml/notification_light_settings.xml
	src/com/android/settings/DisplaySettings.java