add --quiet etc. options to control verbosity

[ghost]

The monitor command outputs text to stdout so on non-Qubes systems an email will likely be sent by the cron daemon each time the job is run (or /var/spool/... will silently be filled if the mta is not properly configured).

Maybe it's enough to redirect stdout to /dev/null but I couldn't find a way to trigger an error with monitor to test if errors are still shown (ie. output to stderr).

EDIT: alternatively monitor could not output anything at all (except warnings/errors of course) and there could be a --verbose option

[tasket]

Good idea.

There is already a little log-friendliness when using the -u unattended option. In that mode, the progress line for send should only update 5x instead of 1000x.

But in future (v0.3 I think) I'll switch to using the logger module and that will give normal verbosity options.

[tasket]

@taradiddles Implemented --quiet mode.