Reason is due to premature terminating postback threads because
the serviceActivityCount is decremented erreously when updating
intermediate job statuses with portal.
Fix is in classifying job status as final or non-final.
As it is, all JobStatus in CommEngine are final; however,
derived classes may have non-final JobStatus.

Achieved by adding the isBroadcastFatal method to Job class.

Thie allows for removal of entries from the original enum JobStatus that more
appropriately belong to derivation of CommEngine.  Such data complicates
the management of the original JobStateus when adding new CommEngines.
These entries can be declared in a new enums implementing
the JobStatus interface, for each derived CommEngine.

returning 422 HTTP status to indicate message is spammed.