spin 1.53

As you may have noticed, but which I haven't written about specifically yet (I will in a little bit, after I finish up a few more things), I'm in the process of reworking my web pages a little. I needed some more support in spin as a result.

This release adds navigation bars at both the top and bottom of each page instead of just at the bottom, if .sitemap is used. It also runs the arguments to \heading through parsing so that macros can be used there. The navigation stuff is still really hard-coded; I'd like to find a better way of handling that at some point, but it doesn't matter all that much while I'm the only person using the .sitemap features.

You can get the latest version from my web tools page.