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 was running IE9 at work, but upgraded to IE11 on Friday so unfortunately can't continue to test the old version. The only issues that I noticed were with the JavaScript create room prompt defaulting to undefined and the JS error when calling requestAnimationFrame.