Setting a Route without Triggering the Router

[Ben-G]

In some cases, when UIKit performs a transition that we cannot force through the router, we need to notify the router about the change (also discussed in #17).

In such cases we might want to update the route, without triggering the actual routing. If the transition already happened directly from within UIKit we don't want to trigger another action in the router.

We'll need to add this to the API of the router in form of a new action. Maybe we could call it NotifyOfNewRoute(route).