WISHLIST:
- maybe use hdf5 instead of the ad hoc binary format
- add real documentation (e.g. sphinx)
- add structured docstrings to the python code (e.g. epydoc, reST)
- add real unit tests instead of just manually executed demos
- allow non-file ways to specify the state distribution and transitions
- allow the forward-backward algorithm to run in RAM instead of on disk
