Floating Window: Welcome back

* Port squashed jellybean floating window to kitkat.

Floating window contributors:
@drcmda
@beerbong
@D4rKn3sSyS

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>

Merge notification manager service changes.

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>

Change-Id: If3d6338f657915754bd6cb9cb987df62c17aa6d0

Conflicts:
	services/java/com/android/server/NotificationManagerService.java
	services/java/com/android/server/am/ActivityStack.java