[feature request] zip file handling

[bertlebee]

I'm loving all the filesystem handling stuff, particularly walking the file system, but it all falls down when I hit a zip file (actually a jar in this case, but whatevs). The only remotely friendly way I've found to deal with zip files in scala is better-files. At the moment I've just pulled in the dep for handling the jars, but it'd be awesome to have support for zip files baked into os-lib, particularly the ability to walk into jars and copy files to jars as easily as os-lib makes these operations on regular files/folders.