input: Add option to toggle pointer icon when using stylus

* The visible pointer icon when hovering or drawing with the stylus is
  quite annoying when trying to actually draw with it. Turn it off by
  default and add an option to turn it on.

Change-Id: Ib7f23e8b69589e3f875d150caf05065b64676e44

Conflicts:
	services/input/InputReader.cpp
	services/input/InputReader.h
	services/jni/com_android_server_input_InputManagerService.cpp
Disable touch while using the stylus (Galaxy Note)

Android 4.0 cannot form multitouch events from multiple input
devices. So it is not possible to report one touchpoint from the
stylus position and, at the same time, another touchpoint from a
finger touch. Instead, when a new input device starts up the currently
active input is cancelled. This is highly undesirable while writing
with the pen.

The easiest solution is to ignore non-stylus touch events while the
stylus is within range (hovering) of the touchscreen. For example,
N-trig digitizers implement this in hardware. But wacom digitizers do
report pen data simultaneously with touch data. This patch disables
(non-stylus) touch input within 50ms of stylus data. On my Galaxy
Note this is necessary to make stylus input usable.

Change-Id: I9f458d85d8bf83d6cf03b467d46ce066fd55b7e0

Conflicts:
	services/input/InputReader.cpp
	services/input/InputReader.h