Start a `wsgiref.simple_server` based server to run this mapper.

def start_server(self, host='localhost', port=9000, app=None):
        """Start a `wsgiref.simple_server` based server to run this mapper."""
        from wsgiref.simple_server import make_server
        if app is None:
            app = self.wsgi
        server = make_server(host, port, app)
        server_addr = "%s:%s" % (server.server_name, server.server_port)
        print "Server listening at http://%s/" % server_addr
        server.serve_forever()