Symfony EventDispatcher updates.

This is an attempt to address issue #1

Tested with latest [Symfony EventDispatcher 2.3.6 stable](http://pear.symfony.com/#eventdispatcher)

`EventsTest.php` is passing. Can you please review to make sure I've not made any mistakes? This was my first time working with Symfony's EventDispatcher. Let me know if you have suggestions or ideas for improvements.

Thanks!