When zipping a directory, allow the parent directories to be elided

[borkdude]

E.g.:

(fs/zip "foo.zip" [{:path "foo/bar/baz" :root "foo/bar"}])

TODO: look at how Python, Ruby and Node.js do this and also clj-commons/fs.

Alternative 1: provide a function to do the renaming of file path on disk and entry in zip