DeltaTickModelReader update #3

* DiveIn block save/open should now work.
* TrackSpecies button is now enabled after model is opened. There must be
  at least one breed in the model for the button to be enabled.
* Added an error popup in case breed name in model does not match any
  breed in library XML. After the error popup, DeltaTick will quit because
  it is not possible to recover from this error.