The method getListenerPriority($eventName, $listener) has been added to the
EventDispatcherInterface.
The methods Event::setDispatcher(), Event::getDispatcher(), Event::setName()
and Event::getName() have been removed.
The event dispatcher and the event name are passed to the listener call.
2.5.0
added Debug\TraceableEventDispatcher (originally in HttpKernel)
changed Debug\TraceableEventDispatcherInterface to extend EventDispatcherInterface
added RegisterListenersPass (originally in HttpKernel)
2.1.0
added TraceableEventDispatcherInterface
added ContainerAwareEventDispatcher
added a reference to the EventDispatcher on the Event
added a reference to the Event name on the event
added fluid interface to the dispatch() method which now returns the Event
object
added GenericEvent event class
added the possibility for subscribers to subscribe several times for the
same event
