appRoute method on the AppRouter

Hey, thanks for your work on this project :-)

I wanted to add regular expression routes to my app and it felt a bit messy having to bind context when the logic was mostly already in the AppRouter object and could be moved around. I felt because there's a route method on Backbone.Router and routes collection a corresponding appRoute method for appRoutes collection made more semantic sense.

I've submitted a pull request with it moved and a spec. Only thing this seems to take away from the previous code is that prior to this controller dependency was injected into the processAppRoutes method whereas with this the controller is determined when appRoute is executed.