string getTrackList( int typeEnum )

This method returns a comma-separated list of CARIS Keys of the tracks currently held by the map which satisfy the type specification given by typeEnum.  The typeEnum argument may be 0, 1, or 2 to get a list of all tracks, tracks with segment highlighting support, or tracks with vertex highlighting support.  If no tracks of the specified type exist or typeEnum is invalid, the returned string is empty, i.e. "".