add process to default log format

Signed-off-by: Steven Armstrong <steven.armstrong@id.ethz.ch>
use default control socket if none given by user

Signed-off-by: Steven Armstrong <steven.armstrong@id.ethz.ch>
use verbose XPUB to be notified of _all_ subscribers, not just the first

Signed-off-by: Steven Armstrong <steven.armstrong@id.ethz.ch>