HeadsUp: open app in fullscreen on longclick

credits to David96

Change-Id: I7083a01e8bc50ecb4885b57d6088163b853cd772

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/BaseStatusBar.java
	packages/SystemUI/src/com/android/systemui/statusbar/policy/HeadsUpNotificationView.java