Improve util.confirm()'s abort_on_unconfirmed option
Improve util.confirm()'s abort_on_unconfirmed option

It can now either an int or str in addition to a bool. If it's an int,
that will be used as the abort exit/error code. If it's a string, that
will be used as the abort message.

wylee/runcommands,wylee/runcommands