framework/base: Add EdgeGesture service.

Based on code of PieService.

PS
- add more sensitive steps

default: 5, minimum: 1, maximum: 10
PS
- fix mask derp
PS
- cleanup
- reduce left and right trigger to from 80% to 70%
  till new size flage for the service are ready

Change-Id: I053737e36340a5ec6814b21eb87575f9689c7e88

Conflicts:
	core/res/res/values/dimens.xml
	core/res/res/values/slim_symbols.xml
	services/java/com/android/server/SystemServer.java