Remove pypi-install
Convert exception handling to Flask style

Part of #273
Fix Travis-CI fo shizzle

Part of #273
Fix authentication in Flask-XML-RPC

This adds Basic HTTP authentication to the Flask-XML-RPC backend and
mimics the old behaviour of the render() function in the Twisted
backend. That includes mangling request and inserting an auth-object
produced by our AuthFactory.

Part of #273