settings: Cleanup and add auto power profiles option

 * Add categories for all items
 * Add helper class for Settings.Secure

Change-Id: I9d8fd6720516e7fa321c05744ada81415cbf8aaa
Merge remote-tracking branch 'upstream/cm-11.0' into cm-11.0
category
Conflicts:
	res/xml/performance_settings.xml

Change-Id: I4f1ad86cda25a9a9a70d45b6bf83ebfc30c0d090