all tables now have full grid lines
CSS: removed some display-specific logic

In particular, the header is now always drawn, even on small-screen devices
CSS: removed unused "nav-fixed" class
CSS: removed clearfix, affix
CSS: nav bars are no longer fixed. They now scroll with the rest of the page
CSS: too-wide tables now have a scroll bar instead of overflowing
CSS: Post titles are now right-justified, so they can't overflow
CSS: The top nav bar no longer line-wraps

The bottom one still does.