code: public void getData(long id, Handler<GpsTrackpoint> handler)
  	{
  		osm.makeAuthenticatedRequest(GPX + "/" + id + "/data", "GET", new GpxTrackParser(handler));
  	}
docs: Get all trackpoints contained in the given trace id. Note that the trace is a GPX file, so
  there is potentially much more information in there than simply the trackpoints. However,
  this method only parses the trackpoints and ignores everything else.
  
  @throws OsmNotFoundException if the trace with the given id does not exist
  @throws OsmAuthorizationException if this application is not authorized to read the user's
  traces (Permission.READ_GPS_TRACES)
  OR if the trace in question is not the user's own trace and
  at the same time it is not public
  OR if not logged in at all