Gifv support

Imgur just released a [post](http://imgur.com/blog/2014/10/09/introducing-gifv/) talking about their .gif solution.
It converts the gif to mp4 and uses the tag video in loop.

The thumbor gif used for testing went from 32kb to 11kb.
[CanIUse](http://caniuse.com/#feat=mpeg4) support matrix of H.264 looks really good.

What do you guys think ?