ss is a modern alternative to netstat. The flags we use and the way we
parse the output are compatible with netstat. Since netstat is no
longer installed on some Linux distributions, prefer ss, but fall back
to netstat if "which ss" fails.
Also tweaks some logging.
Fixes#65
CDC RSync is a command line tool / library for uploading files to a remote machine in an rsync-like
fashion. It quickly skips files with matching timestamp and size, and only transfers deltas for
existing files.