These routes allow us to call any function without explicitly defining
a route for them. TODO: if we can serve these routes from a separate
instance of router (controlled by a commandline flag or env var), we'd
be able to keep this instance of the router "private" by not assigning
it a loadbalancer/nodeport or other externally-visible service.
Router uses poolmgr to specialize pods when necessary.
Router uses controller to get the list of triggers to listen for. For
now this integration is pretty crappy -- we just poll the controller
every few seconds and cache the result. The right way would be to
have some sort of watch API on the controller and use that. Or maybe
share access to etcd directly.