archive: top-level index page with adjusted link text

This is another experiment in our series.  On this one I left the long titles
in, but the basic idea is independent of them.

Here I have attempted to make it so that most people can follow the
organization of the material in a linearized page, or when tabbing through the
links.  Please let me know if it works for you.

I have not attempted to fix the search tool.  

Al