Also react on `transitionEnd` event

This simply makes AnimationUtils also listen to the `transitionEnd` event. This future proofs the module in addition to supporting the non-WebKit prefixed property.
Oops. Well, I guess that's what I get for trying to attempt late night coding... Fixed.

But if the CSS is correctly written, theoretically only one event should be triggered, namely the last one found that is supported, which in the case of Chrome should be the unprefixed versions as of M29 (I think you said the current CEF is based on M29, not sure). :)

If you can wordsmith the new comment, it'd probably make more sense. I wasn't 100% understanding what you said (no need to explain), and I was trying not to make it sound like a direct quote. :\