'Add a new route.
The passed XML Stream C{xs} will have an observer for all stanzas
added to route its outgoing traffic. In turn, traffic for
C{destination} will be passed to this stream.
@param destination: Destination of the route to be added as a host name
or L{None} for the default route.
@type destination: C{str} or L{None}.
@param xs: XML Stream to register the route for.
@type xs: L{EventDispatcher<utility.EventDispatcher>}.'

def addRoute(self, destination, xs):

    self.routes[destination] = xs
    xs.addObserver('/*', self.route)
