Fixed issue #677

Hello,

With this versions of windows, IE can't reproduce html5 media elements, but all functions are aviable, so if you check video.canPlayType !== 'undefined' return true, but if you call the function video.canPlayType("video/mp4") then a exception is throwed.

I add a piece of code that after check video.canPlayType !== 'undefined', I put a try/catch, to check if function work or not, if function throw exception, I set supportsMediaTag = false.