Settings: Add HeadsUp setting.
And Hover Master Switch
Change-Id: Ib7a59145843bedb16aacc87bf6d3c6da143e8d3e

Conflicts:
	res/xml/notification_drawer.xml
Remove SystemSettingSwitchPreference.

We should not introduce one-off UI patterns when there are plenty of
examples where the same usage pattern (a feature on its own
PreferenceScreen with a global enable switch in the action bar) is
handled differently everywhere else (e.g. daydream, cast display,
blacklist). This makes for inconsistent UX.
Also, there are discoverability issues: As there's no other case of a
preference with an embedded control widget opening another preference
screen, users won't expect to find another screen behind it.
Additionally - but entirely subjective - the control looks plain ugly,
as the preference padding is too large for the large switch.

Change-Id: I61284e961babefa3748102b05055fb1d03b079b0

Conflicts:
	res/values/cm_strings.xml
	res/xml/notification_drawer.xml
	src/com/android/settings/cyanogenmod/NotificationDrawer.java
	src/com/android/settings/headsup/HeadsUpSettings.java
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