Prevent a duplicated registration of Observers

If same Observer and same URI are registered, the callback functions are called multiple times
when data identified by a given content URI changes.
It makes system slow and it cause ANR sometimes.
And When run unregisterContentObserver(), just one deleted
but others are remained in mObservers.
So add prevent code to avoid to duplicated registraion of Observers

Change-Id: I5c7845deb682db289ff0d53150ef012174859767
Signed-off-by: muzbit.kim <muzbit.kim@lge.com>
Quicktiles: support flipping at every tile
https://github.com/NamelessRom/android_frameworks_base/commit/7f456d8867b5a26ef075683c7472a78d01b37afa
sorry but the previous implementation was a bit stupid.
DRY (Don't Repeat Yourself)

implement flipping in OnClick, so that every existing and comming tile
supports it.

Change-Id: Iaaf354ba00e4f5aa7dacab42524b1d01f047ab8a
SystemUI: QuickTiles: Allow up to 4 flip animations
https://github.com/NamelessRom/android_frameworks_base/commit/5ee97b29485d3a315e161f9c4956383ddf6755f7
we now have left, right, up and down flip animations.
set flip down animation to default when pressing the tile.

Change-Id: Ida858d6235e681f380172b5de83c127eb9e4a0b3