Start of the refactoring. Commit is quite big because I forgot to use git right from the beginning. Sorry.

new settings page that allows plugins to integrate their own settings dialogs more with the existing ones

This is made using em unit instead of pt for font-size.
"New" sizes are relative to the font-size choosen by the user.

Changed 9pt in 0.95em, 8pt in 0.8em and 7pt in 0.7em, tested on Firefox. This should fix zoom in/out in IE.

<img /> tags need alternative content with "alt" attribute. "dots.png" is not a content. Using CSS backgrounds instead.

"border" attribute is not a valid attribute for <img /> tags. Using proper CSS instructions instead.

<br /> is not a valid strict xhtml1.0 tag. Not semantic. Replacing it by CSS instructions on semantic tags.

center is not a valid strict xhtml1.0 tag (not semantic). At least, replacing it by a div with "center" class.