Update file glob code

[sjspielman]

This PR updates parsing to handle file globs better.

Noting that I tested this locally to see if we can grab all the OpenScPCA docs files, and it worked with "docs/* docs/*/* docs/*/*/*" to get all the nested docs levels. ** didn't change the behavior and all three arguments do seem to be needed.

After this goes in, we'll want to bump the release tag and update its usage in OpenScPCA-analysis accordingly.

[jashapiro]

LGTM. Sad that ** expansion doesn't work, but I guess that is not strictly part of the POSIX standard, just something that a lot of implementations do.