SystemUI: Add EdgeGesture service.

Based on code of PieService.

Change-Id: I5c66e2858c8ddbe9faa0e0640c50714c8d1d5e29

Conflicts:
	Android.mk
	core/java/android/service/gesture/EdgeGestureManager.java
	core/java/android/service/gesture/IEdgeGestureService.aidl
	core/java/com/android/internal/util/gesture/EdgeServiceConstants.java
	core/res/res/values/dimens.xml
	services/java/com/android/server/SystemServer.java
	services/java/com/android/server/gesture/EdgeGestureInputFilter.java
	services/java/com/android/server/gesture/EdgeGestureService.java
	services/java/com/android/server/gesture/EdgeGestureTracker.java