Quicksettings: add a switch to enable/disable custom colors and alpha

-This fixes theming qs background.

Thanks to @gs2usr and Vanir

Signed-off-by: scott <scott@ubuntu>

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

Change-Id: I255426798f88734126684a04e2230a7e05416d8d