InputReader: add 5-point calibration

There does not exist any native x/y touch calibration in Android to adjust
for the very common scenario where a touch screen active sensor size does
not match the display ative size. Using a standard 5-point calibration in
the Android InputReader will adjust for offsets and size/resolution mismatches.
The /data/misc/tscal/pointercal data file can be created using something
like TSCalibration2 [1].

[1] http://git.android-x86.org/?p=platform/packages/apps/TSCalibration2.git

Signed-off-by: Tim Harvey <tharvey@gateworks.com>