Distinguish between period cancellation and message cancellation commands.
Added a message command that produces a cancellation message for the sender.
client-editing-simplification
1people_outgoing_transport: 2debug_print="T: people_outgoing_transport for $local_part@$domain" 3driver=pipe 4command=/var/lib/imip-agent/imip_person_outgoing.py 5user=imip-agent 6initgroups=true