Add martini.Routes service to Classic middleware.
Expose the built-in Routes middleware via the Router interface.
Doco fixes from @codegangsta.
Merge branch 'add-routes-to-classic-middleware' of github.com:BurntSushi/martini into BurntSushi-add-routes-to-classic-middleware
Merge branch 'BurntSushi-add-routes-to-classic-middleware'