A folder is read as its * expansion, so a subfolder, or anything else
that is not a regular file, is now named in the map's file sheet as
skipped, where before it was left out unseen and a folder of folders
gave an empty map. Names beginning with a dot stay out, as the
expansion leaves them. A skipped member takes a file position, so the
files after it are numbered one further on.

The description and README say that @[i] is the same position in
every sheet a call chooses, and the README now states every refusal
the description does. The cache is the user's to manage; the tool
removes no copy.

Release 0.4.0 in pyproject.toml, server.json and SECURITY.md.