better job state management in pm

[johrstrom]

The project manager currently only writes to the job_history.log when a job is submitted. We need better job state management in this aspect of the project manager so that we don't have to continually query for jobs that are complete.

And really, that's why we're doing this: as an optimization. So that we don't have to continually query for jobs that are complete. Instead we should update the job log when a job is complete so that we never have to deal with that job again.