Dynamic height for the demo style switcher.
Don't use automatic detection in the demo.

Since we now have real tests anyway there's no point in slowing
down the demo. It was a bit of a vanity thing considering how fast
it was working on a few dozen languages. Now when there's over 100
of them it's not fast anymore :-).
Move categories into the class attribute.
Merge remote-tracking branch 'refs/remotes/origin/master'