errors should be more obvious
fix typo in my Q translation; also add some basic validation to aid
debugging for script developers
automatically end the Q chain so the user doesn't have to
automatically import the base Resources so the user doesn't have to
make the 2nd arg to Ssh::cmd() optional since it is rarely used
update base resources to work with latest experimental Borg.
also simplify @install() so that skip_if and _static aren't necessary;
hopefully the code is also a little more readable