DevicePose: changed getHeading() to return the heading in degrees and
not radians, to be consistent (degrees all throughout).
PointDouble: Added methods calculateRadiansTo(PointDouble other) and
add(offsetX, offsetY):PointDouble.
Made getDeviceCoords() public.
Corrected the testWithBadINSGoodVINS() method. Too simple though. Will
improve it next time by re-observing a feature (accurately) more times.
Renamed "testBadINSGoodVINS()" to
"testBadINSGoodVINSUsingReobservedFeatures()" to highlight that it uses
feature coords for re-observation instead of observed distance and
heading. Also made the test scalable (you can increase the number of
iterations). Test shows EKF actually worsens the estimates. Probably
because re-observation mechanism is wrong.
Merge branch 'vins-integration' of https://github.com/inpaner/VINS into
vins-integration

Conflicts:
	VINS/src/tests/EKFTests.java