This is the first version actually integrated into the build system. If people think the results are OK, I think we should move merge because it has become more difficult than I thought to update the rst files from man page changes. Of course we can/should still fix any glaring problems. One thing that is not here at all is any kind of automation of the fallback for people without (recent) sphinx. I also left the nroff man sources in the tree, but if I merge this series (or something similar) I plan to delete them.