Model save file bloat

[taalbrecht]

Model save files seem to be including some unnecessary files. To reproduce:

1. Ingest source documents (local files used when bug originally noticed)
2. Build a model and record settings.
3. Save the model file
4. Start a new session
5. Load the model from step 3.
6. Recreate the models with the exact same settings as in step 2
7. Save the model file

The model saved from step 7 will be much larger than the model saved in step 2 even though they should be roughly the same size