[1/3] Settings: Increasing Ringtone

      Option to set the incoming call ringtone volume to increase
      in pre-defined (user selected) increments.

Linked commits:
      Frameworks - https://gerrit.paranoidandroid.co/#/c/448/
      Telephony  - https://gerrit.paranoidandroid.co/#/c/451/

Change-Id: If7b36bd098dc65c8d418d372d4e0017868826a1f