Partly merged the speed sensor and GPSTracker. Disable the tracker (do we need/want it?).
Removed GPX-writer-code. We don't need it as we already put data in main XML-file.
Renamed position sensor to location sensor. Implemented the various attributes. Some restructuring.
Merge branch 'position'

Conflicts:
	src/no_de/inf5090/visualizingsensordata/userInterface/GraphDrawActivity.java