WIP Infer n_features and n_states in CRFs

This is my shot at inferring ``n_features`` and ``n_states`` in CRFs. I just realized that I shouldn't test ``n_states`` the way I do whoops.
This leaves open the possibility of setting everything by hand (for example ``n_states`` if you don't have the full dataset or something), in which case you don't need to call ``initialize``.

Still very much WIP.