Add experimental WSGI server implementation

Forgive all the TODOs; this is just meant to be experimental. I managed to successfully hook this up to Flask; if `python/wsgi.py` is executed as a script, it uses `test_app` from werkzeug, which just echoes back information about the environment. It relies on both `server.crt` and `server.key` being present in the current directory; if you'd like me to commit the ones I'm using for testing, I'd be happy to do so.