framework/base: Add EdgeGesture service.

Based on code of PieService.

Change-Id: I053737e36340a5ec6814b21eb87575f9689c7e88

Conflicts:
	Android.mk
	core/res/res/values/config.xml
	core/res/res/values/symbols.xml
	services/java/com/android/server/SystemServer.java