SysUI: Don't recreate controllers.

The various controllers, such as mLocationController, get recreated
every time the status bar is recreated due to a theme change.  We
should only need to create these if they are null, otherwise use
the controller as is.  Also, each of these controlers registers
themselves as a broadcast receiver and are never unregistered before
recreating them.

Change-Id: I6215aae5a82b7ced8f0f25cf592a804d38825260
Modified "Empty button" > "Leave empty"

"Empty button" implies a placeholder button, which could be confusing to new users.

Change-Id: I092bdb0c8d3cfad79560526f383cdb7efb730a06
Merge "Modified "Empty button" > "Leave empty"" into cm-11.0
Merge "SysUI: Don't recreate controllers." into cm-11.0
Fix the value type of def_noise_suppression

Change-Id: I0b94e9b24af959fa1c16c807ba83890b2ce077ad
Keyguard : Fix album art sticking after playback is stopped

newIsNull should be populated by what is currently being set and not by
what the user's custom background is, since otherwise you end up a in state
where the user has no custom background set, music stops, no album art via arg is provided and you simply return.

Change-Id: Ifaea1cae176faaba6b32a711071f3b75ccacdd63
Merge remote-tracking branch 'CM/cm-11.0' into cm-11.0