Error Message when file upload is too large

Noticed a JavaScript error in IE9, which was caused by the call to
requestAnimationFrame in loader.js. Added client side checking of spaces on room name when creating a new room (fix #1191). Added custom error message for when a file upload is too large (fix #1190).
I'm getting the impression that you need to support IE8 - if this is the case, are you up for dropping into meta at some point to let us know if anything else is broken?