Update the touchscreen plug-in.

Update the touchscreen plug-in.

Now works with bcm5974: Added manual contact tracking for drivers that
do not report a tracking id and fixed abs limit querying to use
ABS_MT_* instead of ABS_*.

Fixed reported area: The incoming point was the top-left point instead
of the center which was incorrect.

Added pressure support.

Tracking of event type has been removed as handleTouchEvent no longer
needs it.

Broken debug prints have been removed.

Changed udev auto-detection to pick only /dev/input/event*.

Fixed multiple released state reports with some drivers.

Name and capabilities are now set properly for the QTouchDevice.

Change-Id: I8f026c9a14465bfb6d567f4dcf36c5c03f843868
Reviewed-by: Jørgen Lind <jorgen.lind@nokia.com>