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
Merge "Framework: Make Safe headset volume user configurable (1 of 2)" into cm-10.1