clean 6.x-1.2

- #361703 by psynaptic: Fix missing logo issue.
- Fix autocomplete widget issue where margin was causing horizontal gaps between options.
- Reduce font-size of messages; convert tabs to spaces.
- Move all CSS files into css/ subfolder.
- Removed duplicate padding property from navigation.css.
- Adding padding to input.error to account for change in border.
- Adding extra height at the top of the page for simplemenu/adminmenu.
- Moving screenshot into root folder.
- Moving tabs CSS into navigation.css.
- Moving non-color related styles out of color.css.
- Moving more CSS color properties to color.css.
- Slight change in structure of conditional comments - purely superficial.
- Moving node classes to template.php.
- Changing base fonts to more common set: Arial, sans-serif.
- More sensible leading for headings: 1.1.
- Adding margin bottom to address tags to match p.
- Moving more colors to color.css and forcing select tag to inherit font-family.
- Changing font size on help div.
- Reorganising CSS files: removed custom.css, added htmlelements.css and typography.css.
- Adding Table section to htmlelements.css.
- Changing font size of tabs and blocks, reduce bottom padding on fieldsets.
- Removed node-blog.tpl.php as it is not required.