CSS refactoring (resorting and indexing)

This PR is solely a commit of the css files refactoring, as made by Ant. Please check the diff - IMHO the web interface on github gives a good view on this one - or of course your preferred diff/merge viewer. It looked ok to me (but I'm a bit low on time for this) and I'd appreciate confirmation.
@StealthWombat Thank you for pursuing your refactoring intention in batches, this batch is way easier for us to follow since it seems refactoring alone, and not everything at once. (and a linklevel tweak?).

> This is mainly just a resorting and indexing of CSS file content, as talked about here:
http://www.elkarte.net/index.php?topic=439.msg3242#msg3242 and the next post.
Stuff still needs to be split from index.css to the variant files,
but I thought it better to try and get index.css organised first.
It's still a horrible mess, but at least it's easier to see
where the problems are and how to fix them.
Code has been run through CSS Comb to get consistent order in declarations.
Some redundant and/or deprecated tags etc have been removed.
Also, applied some small (tested) styling tweaks here and there.
Those should be prefectly safe.:)

Signed-off-by: Norv <a.w.norv@gmail.com>