Refactor Werkzeug requirement into flask

This is a PR for discussion is a rewrite of the code base that removes Werkzeug and replaces the server code with a Flask implementation - see issue #38 .
Do we need haml for the initial first pass? I would try to leave this out if possible - it's an extra technology to review and would slow down the process of getting us up to speed with Flask. I don't think we need any HTML initially, just the existing JSON interface.