Revert "Settings: Add heads up blacklist options. (2/2)"

This reverts commit ca559b9ff57c85295d23a3d3de49dc81b6a45911.

Conflicts:

	res/values/cm_strings.xml
	res/xml/notification_drawer.xml
	src/com/android/settings/cyanogenmod/NotificationDrawer.java
	src/com/android/settings/cyanogenmod/SystemSettingListPreference.java
	src/com/android/settings/headsup/HeadsUpDoNotDisturbSettings.java