100% test coverage, overall improvements

Hi,

This is a big fat pull request, sorry about that.
If you don't want it, feel free to decline.

I basically made fysom a deployable python module with 100% test coverage. 
Your code is working very well, so aside from a few minor refactorings, I didn't change anything in the original fysom.py.
It's on PyPi now, I can share the login if you'd like.