Packs ALL directories explicitely

It looks like TAR needs this to restore directory permissions correctly.
More sanity checks for TAR archives
Renames 'envp' to 'environ'
Fixes path problems
Use --numeric-owner

If untaring with -p and no user by that name exists, it looks like tar
would use 0 (root) instead!
Implements copying /bin/sh in vagrant (ugly perl)
Runs tests/run.py non-interactively on travis