Allow persistence of input device calibration

This patch extends the PersistentDataStore store to read and write
input device calibration data. A new SET_INPUT_CALIBRATION permission
grants apps the ability to update this information, and a new
TouchCalibration class is used to wrap the raw calibration data.

Change-Id: I4daac2b15ef03616ea5b068c1e77bebd0ce7b8c1