Support GESTURE_SENSOR input device type with GestureService

* The GESTURE_SENSOR input device type is meant to support touch sensors
  which are meant for gesture input only, very similar to a touchpad,
  but without the pointer capability.
* Define separate service to handle gestures from GESTURE_SENSOR device
  type.

Change-Id: I9b273df2a3cc141774d7f7cd81e43a90ea5b230b

Hide InputDevice.SOURCE_GESTURE_SENSOR from API

Change-Id: If009e9595fc593594b0e7764669996de137483a1

GestureInput : Allow doubletap/longpress configuration

Allows devices to specify pending intents for double tap and
long press events.

Change-Id: I7e7cc2f9f96a01d8f6232e5cf0e19832fdfd5359

Conflicts:
	Android.mk
	core/res/res/values/config.xml
	core/res/res/values/symbols.xml
	services/java/com/android/server/SystemServer.java
GEL Integration (1/2)

Changed INJECT_EVENTS permission from signature to signatureOrSystem.

Change-Id: Ie3633aa2ee7a2f22b7f32232ce4d3d98f33fd39d