Framework: Add notification rows transparency (2/2)

Patchset 2+3
-rebased

Change-Id: Ifdca707989fe836a2a0b46869da808e0750494d8
add a java class ShitChangedObserver

observes changes for notification drawer wallpaper/alpha and notification rows alpha and invokes the setNotificationWallpaperHelper() method to apply the new changes

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