[Feature request] Controller class/method not found scenario

`bramus/router` is not only my favourite router for 'vanilla PHP' with great functionality, it is also great for education: we are using the router in our PHP labs because of its very clean and clear interface.

It would be nice if the router would do something else than showing a blank screen when the controller class or controller method is not found. I was thinking of either throwing an Error or returning some HTTP status code / message (but different from **empty** 404). It would make debugging easier for PHP students 😊