Added "remove" command.

Hi.  I've found the Barista library extremely useful thus far, feeling its strongest feature is the ability to add complex routes at runtime, separated from the process that actually interprets those routes.  

My needs, however, required the ability to remove routes on the fly as easily as add them.  I did so by using your undocumented "name" feature along with creating a router.remove( name ) method.  Since I'm finding your library so useful, I figured I'd "share the love" and give back the additions I made.

I did my best to match your coding style, and included complete (I hope) tests to verify and prove it.

Thanks!