Replaced $.cleanData-hook with $.event.special

Don't need to change jQuery's cleanData + does the same
+ Gains some performance (about 6 to 8% in my tests)
+ Could be further improved because the handler is only called for the
removed element. So we could remove the $.Event-arg. plus the filter in
the handler.

(Will provide additional info / tests as opposed here jquery@0a0a39f896f83412dc91bedd6819c3a3a0932302 if someone told me where to put them)