Only create URLs when we've found a route that matches
Handle optional parameters when parameter doesn't exist on the hash
Throw an error on go() when no method or matching route exists
Fix error when trying to find a url when no routes exist on the router
Fix bug in specs
Call router method with params hash
Fix bug when calling _.keys on a non-object
Fix bug in specs dealing with a route to an empty string
Fix bug in specs with passing an options hash to go()