Router Symfony Parameters
Hi,

The Router class allows to use the power of Symfony routing system. That's really great ! But there is now way to get the parameters matched by the routing system and using it in a server.

The `Ratchet\Http\Router` passes a `Guzzle\Http\Message\RequestInterface` to the `onOpen` method. The thing is that `RequestInterface` is not aware of the route format and so of the parameters.

I want to include this functionnallity, but I don't know, what's the best solution.

Thanks
