SystemUI: A proposal for a new quiet hours icons

 PS2 added xxhdpi icons
 PS3 removed xxhdpi icons
Change-Id: I87e660210e2089d1bb09da47d39695bbda2889af
Fix certain setting writes being incorrectly skipped.

If a value that previously had a very long value (over the 500 char
threshold) is now set to null, isRedundantSetValue would incorrectly
return true even though the value was changed.

Change-Id: Ia5304743024ec01024be98aa51ed260d38caf93c
Merge remote-tracking branch 'upstream/cm-10.2' into cm-10.2