Add DEFROUTE.

DEFROUTE provides a traditional Lisp S-expression mechanism for defining
routes(as opposed to @url). DEFROUTE is used exactly the same as @url,
and leverages identical underlying machinery. However, it will play nice
with emacs/SLIME considerably better.

It also looks more Lispy to some.
Merge pull request #18 from pnathan/master

Add DEFROUTE.