Halo: Add master switch to disable Halo (1/2) And fix halo button
-Port master switch from @Der-Schubi.
-Fixed Halo not showed at first notifiction pulldown.

Signed-off-by: anerik <anerikgames@gmail.com>

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

Change-Id: Id35041d482cfb85183d41faea58bb5b268a21ca4