Escaping hash characters and whitespace is _not_ supported as neither
are valid element/attribute names (e.g. <foo#bar /> is invalid
XML/HTML).
Escaping single/double quotes also won't be supported for the time
being. It's quite a pain to get this to work right in not just CSS but
also XPath and XML/HTML, for very little gain. Should there be enough
users with an actual use case (other than "But the spec says ...!") I'll
look into this again.
Fixes#124
Yorick Peterse
44630c27ff