Framework: Enable multi-user support for Quiet Hours

Change-Id: Ica967ff6bf5842a08421583449876ba73de13d51
Framework: Enable multi-user support for Notification light

Change-Id: I4fb84fdb0c9e1592c2a421011c303a789cde8c8c
Framework: Fix multi-user support in AudioService

Change-Id: Iddeeeac0734a237103e238bcdaa1e85806a64e4f
Framework:  Fix security exception

Change-Id: I4fa1f55c8209e6890b6cea13b0ed4d781f9f615d
Framework: Make Safe headset volume user configurable (1 of 2)

Patch set 1  : Initial commit
Patch set 2  : Alternative approach using content observer to
               listen for settings changes and react dynamically
Patch set 3  : Rebase

Change-Id: I0bd57334ca1307786eaed6578b216323e442f00e