Improve display when JavaScript is unavailable.

Rather than have the no-transforms class added to the body if the browser doesn't pass the transform support test, this commit reverses this so that the no-transforms class is there by default, and is then removed if the transform support test passes. It also tweaks the CSS so that fragments and speaker notes are visibly displayed in this situation.

This way round, it means that if the JavaScript does not load for any reason (e.g. bad connectivity) or is otherwise unavailable, the content is still visible and able to be read. I don't think this should affect behaviour in any working browser, as it purely changes the point at which the class is set.

I hope that's helpful.