Removed #sidebar-first, #sidebar-first-inner, #sidebar-second, #sidebar-second-inner and moved styles to .region-sidebar-first, .region-sidebar-first .section, .region-sidebar-second, .region-sidebar-second .section.

Renamed #navbar div to #navigation, $navbar region to $navigation, .with-navbar class to .with-navigation and added #navigation .section div

#375953: follow-up, change sidebar primary/secondary to first/second to match proposed D7 region names.

#200495 by JohnAlbin, caroltron, and Toe: Split up monolithic zen.css into smaller, logical stylesheets