docbook2odf: add missing zip dependency (TODO: add needed perl modules)
docbook2odf: fix license
perlPackages.XMLSablotron: new package (FIXME: make it build)

Needed for docbook2odf (which I'm going to package).
docbook2odf: add perl packages (but they don't build yet)

zip command isn't needed when using Archive::Zip module.