Register a class instance to handle a URI.

        :param uri: string - URI for the request
        :param service: StackInABoxService object instance that handles
                        the request

        :returns: n/a

def register_subservice(self, uri, service):
        """Register a class instance to handle a URI.

        :param uri: string - URI for the request
        :param service: StackInABoxService object instance that handles
                        the request

        :returns: n/a
        """
        found = False

        self.create_route(uri, True)
        self.routes[uri]['handlers'].set_subservice(service)