Null should be replaced with \fffd REPLACEMENT CHARACTER (�)

[facelessuser]

This appears to be something that escapes should translate to (\0) and also literal NULL. All of the parsers used by BeautifulSoup remove any Null characters from HTML source, so searching for NULL is impossible. On top of that, the CSS spec states that NULL characters should be replaced with \fffd REPLACEMENT CHARACTER (�). Hex escapes should not translate to NULL, but also translate to \fffd REPLACEMENT CHARACTER (�).