Instead of checking if `options.quiet` is set whenever printing, disable
all printing to stderr if the `--quiet` flag is passed.
Although it isn't strictly necessary, I still don't construct a progress
bar if `options.quiet` is true, since progress bars might be a little
more expensive than just printing error messages.
A future diff might add checking to the `errln` and `outln` macros, so
that they don't print at all if the respective output stream is
inactive.
type: reform
42e20a4a6a