Add support for new input sources.

Added several new coordinate values to MotionEvents to capture
touch major/minor area, tool major/minor area and orientation.

Renamed NDK input constants per convention.

Added InputDevice class in Java which will eventually provide
useful information about available input devices.

Added APIs for manufacturing new MotionEvent objects with multiple
pointers and all necessary coordinate data.

Fixed a bug in the input dispatcher where it could get stuck with
a pointer down forever.

Fixed a bug in the WindowManager where the input window list could
end up containing stale removed windows.

Fixed a bug in the WindowManager where the input channel was being
removed only after the final animation transition had taken place
which caused spurious WINDOW DIED log messages to be printed.

Change-Id: Ie55084da319b20aad29b28a0499b8dd98bb5da68