Use reason field in Broadcast to record reason for pause, cancel etc.

Improved reponse text to pause and resume commands.

The service threads do not terminate immediately, but, instead
each service thread picks up one more job before terminating,
causing servicing more jobs which are not reported back to portal.

This happens when all remaining jobs are being serviced by
service threads when PAUSE is initiated.  Similarly fixed
for CANCEL.

before progressing to COMPLETED state and issue state change
notification to portal.

Also make state change report to be a single line for ease
of grep'ing log file.