Feature/modules

Analytics logic can be referenced as a waltz.module rather than writing it within your main.py

## old 

    import waltz
    urls = ('/analytics/?', 'Analytics')
    app = waltz.setup.dancefloor(urls, globals())
    class Analytics:
        def GET(self):
            web.header('Content-Type', 'application/json')
            return waltz.db().get('analytics')

## new

    import waltz
    urls = ('/analytics/?', 'waltz.modules.Analytics')
    app = waltz.setup.dancefloor(urls, globals())