Launch Heads Up in floating window [1/2]

Change-Id: I530c3d9473e8b0600db047ce2137ee3d44592111

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