Add option to specify SSH command (a-la rsync)
Change --sshcmd option to --rsh to match rsync command syntax
Improve the handling of stdout/stderr from the remote

This should help with OpenSSH ControlMaster (a la GH#37), but it'll be of
benefit to everyone, I think, as the control code is cleaner now.
Add a --quiet option

For when you really would prefer not to know much of anything.
Add a new option, --data-source [Fixes GH#10, GH#17]

Specify a different block device to read from.  Not something I'd be
inclined to use myself, but when two people take the time to submit PRs for
the same issue, clearly there's demand for it.
Merge remote-tracking branch 'deriamis/sshkey'

Conflicts:
	bin/lvmsync