! Prevent duplicate calls to add_css_file() from adding the same file twice. I guess there could be situations where it's desirable, but until someone gives me a proper use case, I'll just prevent it, making it possible to include your file as many times as you may need it, without having to keep track of it. (Subs-Cache.php)
* Another of these useless rewrites I've been working on for weeks... Some rarely called pages (move topic, report post, etc.) well declaring their CSS in the main CSS files, which I've always found to be quite rude. They're now getting their very own file, 'pages.css', yippie. (TEMPLATES: Errors, Login, Mailer, Merge, MoveTopic, Poll, Post, Split;

- #whoisviewing isn't used, AFAIK. (sections.css)

@ The change only reduces CSS filesize by about 300 gzipped bytes (or 1.3KB unzipped), but it's still a good thing to do. It's totally worth the extra work.
- Forgot to remove #fatal_error. (sections.css)