Set a 320px min width for the html.

Less than 320px really screws up the content. So why bother.
Make the content zoomable on mobile devices

Have no clue why it wasn't so to start with.
Refactor .menu code to use min-width & 25em break.

Also introduced a new screen break at 25em to make the menu items
display one after the other for really small screen widths.
Turn on text kerning.
Show the photo/logo in header only at 56em
Change headings font to Source Sans Pro.

Also, related adjustments to letterspacing, etc. Also include new
Google fonts combined link.