Static and Websocket Routes

I finished working on this, as a stop gap between now and Plug middleware because it gets asked for on IRC often enough. It refactors the router.ex to allow for routes similar to:

```elixir
static "/public_route", "/static_dir_to_serve_from" 
websocket "/my_ws_route", WsHandler
```

I updated the README to show examples. @chrismccord if you've decided on which websocket lib to use I can update this to use that, and I can also update it to use multiplexing. 

This doesn't NEED to be merged but I wanted to show how it could be done.