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)

PatchSet2 : Removed all whitespaces

Change-Id: Idbecb8a5f8b54a2782760ab9eaa3ebd0d87e5318