SystemUI: Add EdgeGesture service.

Based on code of PieService.

Change-Id: I5c66e2858c8ddbe9faa0e0640c50714c8d1d5e29

Conflicts:
	core/res/res/values/pa_symbols.xml
SystemUI: Use EdgeGesture service to trigger Pie

EdgeGesture service triggers Pie when detecting gestures on
the WHOLE edge, not just the center.

Patch Set 2: Better trigger values

Change-Id: Id7d9d7f6f5a37ca3696cdddf0da78c88c067970e

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/pie/PieController.java
SystemUI: Position Pie at gesture's triggered position

As the EdgeGesture service is triggered at the whole screen
edge, place Pie at the gesture's triggered position, instead
of always positioning it at the center of the edge.

This might be controversial and a matter of taste, but in
particular on tablets it's sometimes hard to hit the exact
center of the edge and therefore gestures often fail. Could
also imagine enabling this feature on tablets only. Needs
some discussion...

Change-Id: Ife28ac434667148583b34bcccd11262c111b5a67
PhoneWindowManager: add ability to use EdgeGestureService for system gestures.

Update: Default to enabled

Change-Id: Id4e2c0d82f771cd1c20e9196fb6db347494cca69

Conflicts:
	core/java/android/provider/Settings.java
	policy/src/com/android/internal/policy/impl/PhoneWindowManager.java

Conflicts:
	core/java/android/provider/Settings.java
	policy/src/com/android/internal/policy/impl/PhoneWindowManager.java
SystemUI: Stick Pie to edge on phones

Apply the same UX of AOSP's navbar on phones to Pie
controls. When rotating the phone, Pie now sticks to the
same physical screen edge, to which it was pinned before. As
most people start holding their phone with two hands in
landscape mode, keeping Pie at the right or left edge might
be more comfortable to reach by thumbs. The behavior on
tablets should not be affected in any way by this change.

Changes:

PieControlPanel stores only the absolute gravity (the
rotation independent position in portrait mode) of Pie.
PieMenu and PieController query the gravity from Panel.
Query methods (getOrientation(), getDegree(),
isGravityPossible()) only return the relative gravity (the
position depending on current rotation). Therfore, only the
PieControlPanel is aware of, whether and how gravity is
converted.

The amount of snap points is reduced in landscape mode,
because Pie cannot be pinned to the top edge of the screen.

Change-Id: I263f16e1c59e134f374b9a3a007ecdce2d54dc46
SystemUI: Fixed stick Pie to edge
SystemUI: Force Pie centered on small display devices

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/pie/PieController.java
Take out