Note that this is the old CSS2 syntax, we don't support the CSS3 syntax
just yet. Also we don't actually implement the pseudo-elements, this is
really just to make the selectors distinct from the same ones without
these pseudo-elements.
...{All} to ParentNode. Exposes createDocumentFragment and
createComment on Document. Stubs out the document.body setter.
Also adds ParentNode back :^).
These are pretty rare, but they do come up in some places and it's not
hard to support. The Gfx::Font information is approximate (and bad)
but we can fix that separately.
