- Let ssi_server be run from any directory (#include paths relative to file).
- Set up ScrollSpy on options page.

x Write docs on how to iterate with ssi_server.
x Tweak display of "dygraphs" banner in nav.
x Move per-axis.html into new site.
x Get menu items to display in a stack on mobile.
x Move div#main into header.html.
x Reformat options.html to not look bad on mobile.