Fix alignment of navbar button.

Remove the left margin to get the button line up nicely with the left
edge of the logo image, and the left edge of the main body content.
Reduce sidebar title size.

Also use a more semantically-correct h1 tag for these titles.
Reduce size of side bar.

With the reduction in font size of the headings, the side bar can now be
quite a bit smaller. This might help with the border issues...
Merge branch 'visual-design-snags'

Fix up a couple more minor issues with the site design.