use the actual default port for RouteMaster

For some reason the markdown is not rendering correctly when using `<routemaster_port>`. That is the only reason for this PR so something shows up as the port. It does make copy/pasting easier as well.

![screen shot 2014-10-10 at 11 57 50](https://cloud.githubusercontent.com/assets/66143/4591466/4d804698-506d-11e4-8048-0ff21d38c275.png)

^ broken rendering