Add Hover tile

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/phone/QuickSettings.java
Heads up master switch (1/2)

Create a global heads up switch to enable/disable the same.
The user still need to set each app in Settings -> Apps

PS: disabling through master switch will automatically turn of  call ui and mms heads up notifications

Change-Id: I650e230d275247251435c5cfeb728e375e927045

Conflicts:
	core/java/android/provider/Settings.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java

Conflicts:
	core/java/android/provider/Settings.java
Headsup tile

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/phone/QuickSettings.java
QS: Update heads up tile icons

The bell icon for the "on" state look a bit crappy.
Update them too look more lika a bell.

Screenshot: http://goo.gl/rC1VFD

Change-Id: I9a6a54a5ee9ac0100ebf749ee3babe02eb0e2e32