Dbl click bug fix (& loading class for image block), IE9 support (2d tra...

Hi, there! 

I've found some bugs and fixed them.

1. If you click twice while image is loading it will cause two figure blocks appearing. I've added "loading" class to image block, it can be also used for adding loading spinner.

2.  IE9 doesn't support 3d transitions, I've added test for 3d transitions and in case browser doesn't support it it will use 2d transitions instead. There is another story with mouse cursors, but my solution uses separate css file and I didn't add it for pull request.

PS: I'm novice with Forks & Pull Request, if I've done it wrong please tell me.