Add back increasing ring feature (2/3).

Change-Id: Iafc79a57651db327a100e0f1723b62f442b638be

Conflicts:
	res/values/cm_strings.xml
Add back Notification ringtone title
Fix NPE.

When entering the notification prefs sub activity without the increasing
ring pref being visible and leaving it right away, onActivityStop()
threw an NPE because the handler wasn't yet constructed.

Change-Id: Ia4291d8ac3d1dbf76d432db7e0e973844163c4ae