Quick Settings: Swipe to switch

Adds the ability to switch to/from Quick Settings, using a sideways
swipe gesture.
Video demonstration: http://www.youtube.com/watch?v=jZaDVBIFAuA
(Video for the initial Patch Set only)

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