Some tweaks to the Event Manager:
- BC BREAK !: Trigger now returns false (instead of true) if default was prevented - for nicer flow where you can do:
    if (!$eventManager->trigger(Event::getName()) {
        echo 'not continuing default';
    }
- Should no longer throw exceptions when propagation has been stopped or default prevented (due to not implemented MD Foundation method).
Full test coverage on this lib.