Sensors HAL iterative update for jb-mr2

Sensors HAL iterative update for jb-mr2

Specified more precisely what the uncalibrated magnetometer should be
Added uncalibrated sensors event struct
Specified that rotation vector and game rotation vector have to use gyroscopes
Added magnetic field rotation vector
Added accuracy field to rotation vector and magnetometer rotation vector
Added section on comparative importance of batching different sensors
Specified that one-shot sensors must deactivate themselves before sending an event.

Change-Id: Ibc30ce6fc30e698af49a91930bd5a8316b6568b9