Lot of work on classes packing and other misc features

* We now use Symfony's ClassCollectionLoader class to order our PHP classes by their hierarchy. The method fot that is private, so we have to use Reflection to access it :-/
* Added "QueryPath" library Pack Profile
* Added a "EventsPacker"
* Added a "HooksPacker" (that one was a tough guy to implement)
* Our PluginPackerBehaviours now implements ApplicationAwareInterface
* Removed some warnings in "IOUtils#rglob()"
* Added a Plates BaseExtension class
* Misc tiny code modifications