[3/3] services/Telephony: Increasing Ringtone

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

Linked commit:
      Settings   - https://gerrit.paranoidandroid.co/#/c/447/
      Frameworks - https://gerrit.paranoidandroid.co/#/c/448/

Conflicts:
	src/com/android/phone/Ringer.java