- Added test for track ID in track reference

- Added test for track ID in track reference
  (fixes break if no track with this ID is present in the stack)
- Updated the method ReconstructibleTracks():
  now a track is reconstructable if it leaves a hit in one of chambers 1 or 2,
  one hit in chambers 2 or 3, one hit in chambers 4 and 5 and
  3 hits within chambers 6,7,8 and 9. Previously a track had
  to have 10 hits deposited in the spectrometer, one in each of the 10 chambers
(Hermine)