Settings: Add preference for EdgeGesture service.

Update: Default to true

Thanks to mik9
Change-Id: I0325b0a9aa6eb943b48483aebe151726a2c64ac4

Conflicts:
	res/values/mahdi_strings.xml
Settings: Option to hide Adb notification icon (1/2)

Conflicts:
	res/xml/development_prefs.xml