Sensors HAL changes

Adding HAL changes for the following
i) a method to place the HAL in a special mode.
     Expect to use this method for data-injection.
ii) a method to inject sensor data into the sensors subsystem.
iii) New sensor type for a SYNC event (google custom sensor).
iv)  New sensor type for a nudge gesture (google custom sensor).

Change-Id: Idf0479b6301c5363cf51938e23aabc790b69fa96
1 file changed