Does not preserve order of CSS that drupal core does + 960 issue

1) In drupal core items are ordered differently if they're set to $preprocess or not, even with $preprocess_css disabled.(see drupal_add_css around where it's making it's different style tags and pay look how $preprocess is used). Copied how drupal core does it as far as order; results in 3 style tags where 1 was (1 for module, 1 for theme, 1 for preprocess/other).

2) 960 re-orders css so it's css is at top and puts that into css_alt instead of css (not sure why it doesn't just use $vars[css]). May be an issue for 960. Added a check for css_alt into my patch also since it's a common theme).

Ee, and while investigating I separated the processing code into another function with a variable around it so that people can disable it from running twice when they want to (which they will need to do for 960 since 960 overrides $vars[styles]).