Here's what works so far:
* The `route` decorator checks its inputs correctly. There's a nice utility
for doing this, and it's working quite well at the moment.
* The `route` decorator emits a `route_fn` and a `route_struct`. The `routes`
* macro prepends the path terminator with the route struct prefix. The
* `Rocket` library can read mount information (though not act on it properly
just yet) and launch a server using Hyper.
