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)

Patch Set 2: Flip animation follows your finger
Patch Set 3: Fix commit message
Patch Set 4: Fix commit message (again)
Patch Set 5: Pin down the statusbar during swipe
Patch Set 6: Smooth out animation after releasing swipe
Patch Set 7: Swipe in any direction to switch views
Patch Set 8: Ensure the statusbar is properly pinned down
Patch Set 9: Fix logic and event handling issues
Patch Set 10: Refactor for readability
Patch Set 11: Limit swipe detection to the bottom bar

Change-Id: I3cab45f72fe3c5fa40d4631fc6a84ea7bfe51bd1