Ie8 accordion

Currently the accordion causes both ie8 and ie9 to lock up when you click a panel header. This hack skips animations in CollapsableMixin which works, but there must be a cleaner way to employ ReactTransitionEvents, right?
Oh, I see, it affects ie9 also. How about using conditional compilation tags to checj the jscript version: http://msdn.microsoft.com/en-us/library/ie/121hztk3(v=vs.94).aspx

I really dislike UA sniffing.