Quiet Hours: Clean up and consolidate code

- Added: Allow disabling of system sounds

Ported from cm-10.2.

Change-Id: I7d2619becb99c336d23896a672136f491d972abd
Port Forward Quick Unlock

PS3: Fix whitespace and author.

Change-Id: Ic64c47bb35ee4da13b0332d853725a6ef60ac8d4
Merge "Port Forward Quick Unlock" into cm-11.0
Merge "Quiet Hours: Clean up and consolidate code" into cm-11.0
Merge remote-tracking branch 'cm/cm-11.0' into cm-11.0