[Draft] Route parameters support

**Performance**
It shouldn't degrade much as there are no expensive calls:
 - `compile()` was already called during route matching and it caches its result
 - `preg_match()` values are short strings
 
**Design**
No idea how to pass `$this->routes` to `Router` nicely

**Usage**
```php
/** @var $app Ratchet\App */
$app->route("/object/{id}", $objectController);
```
```php
// in $objectController class
function onOpen(ConnectionInterface $conn)
{
    $objectId = $conn->parameters['id'];
}
```
```js
var listenerConf = {url: 'ws://localhost:8080', topic: '/object/2'};
```

**Use case**
1. I have AngularJS app having similar routing scheme (`object/{id}`), so it would be extremely nice to be able to subscribe to relevant route and pass `{id}`. This way I can use for easy notify users having open relevant object ONLY. 
2. As layer to something like [firebase](https://www.firebase.com) maybe?

Tell me what you think.