Move the sorting 5.4 functions to PHP 5.4 class

Moving the sorting functions to the 5.4 class. I also took `aasort` in the new class as it isn't used anywhere in particular in the code (ran a grep against it) and it's probably a helper for the `make_comparer` called through reflection. If you think that it's not called at all for some reason, it might not be needed (although it's probably a helper for the comparer).