Currently, when running jobs on remote machines, --transfer uses rsync
-rlDzR to send files. Among other things, this transfers symlinks as
symlinks instead of following them (the "-l"). I would like to copy
symlinks as real files (which I think is rsync -L). It strikes me
that other people might want different rsync options, so perhaps a
general mechanism is best. We could have an --rsync-opts flag, that
just sets the rsync options; or we could have a --transfer-prog that
lets you specify a different program entirely (like scp). Thoughts?
