Continued changes to web interface for new design.

Added a new font "Volter" for header use, available at
http://www.dafont.com/volter-goldfish.font
Updated headers and buttons to use Volter.
Redesigned large menu buttons to use CSS3 and avoid image use.
TODO: Simplify button HTML to allow vertically-centered text.
TODO: Change CSS for smaller buttons to match the larger ones.  (Possibly with
one parent class whose properties apply to both.)