No content yet other than man pages. To make the man pages render
nicely in mkdocs, I removed the static %-headers and put the code for
them into default.md.tmp.do instead. That way, the raw input redo-*.md
files will look right in mkdocs.
The new format is just a list of .do files we tried, with a newline
after each one. If we successfully found a .do file, we exit 0, else
we exit 1.
As discussed on the redo-list mailing list, it's easier to parse
without the extra cruft. This makes users figure out $1 and $2
themselves, but that's not very hard, and maybe for the best.