Add clarification on ordering of middleware if Route is used

[sjanuary]

An issue was raised in express where a Route was created by calling router.route, then some middleware was added to the Router, then some method handlers were added to the Route. The user expected the middleware added to their Router to be called before the Route's method handlers, but in fact it was not because the Route had been created first and that controlled the precedence of it's handlers.

It might be good to add a short note to the router.route API docs to mention this.

[crandmck]

I believe this is addressed by #579 and #580.