spin 1.27

Finally finished a modification that I've been wanting to make to spin for quite some time. It now looks for a .sitemap file at the top of the source tree and uses that to figure out the structure of the web space for navigation links at the bottoms of each page. It doesn't, as yet, generate an HTML sitemap, but that should now be fairly easy to do, and I think I now know how to get it to pick up changes in page structure automatically and regenerate the appropriate pages (although that may require some restructuring to other parts of the code).

This is the first in a series of changes that I want to make to publish some more information on my web pages. The next is to have a file that tracks the version numbers of all of my released packages so that I don't have to edit the web pages by hand when I release a new version, and so that I can easily include the version number next to download links for scripts.