create interface for Orientation class
improve description
define Context and SensorManager in constructor
check if sensors exist
add methods to register and unregister for sensor events
implement setAcceleration
implement setMagneticField
extend callback interface with orienteationUpdated()
use Orientation class in Navigator
implement Orientation class in LocationService, get sensor events and pass them to the Orientation class.
calculate orientation from sensor values
wrap long lines
Merge branch 'master' into orientation
refresh rate is in microseconds, not mode
fix coding style : Method comments should end with a '.'
switch should have a default
add final modifier
Sensor value arrays have size 3;
predefine size of rotationMatrix and orientationValues
Bearing is also accurate if Orientation is accurate, issue #41
store calculated orientation and timestamp in class property, issue #41