Submit a job script to the queue.

def _submit_to_queue(self, script_file):
        """Submit a job script to the queue."""
        if sys.version_info[0] < 3:
            process = Popen(['qsub', script_file], stdout=PIPE, stderr=PIPE)
        else:
            # need string not bytes so must use universal_newlines
            process = Popen(['qsub', script_file], stdout=PIPE, stderr=PIPE, universal_newlines=True)

        out, err = process.communicate()
        # grab the return code. PBS returns 0 if the job was successful
        queue_id = None
        if process.returncode == 0:
            try:
                # output should of the form '2561553.sdb' or '352353.jessup' - just grab the first part for job id
                queue_id = int(out.split('.')[0])
            except:
                # probably error parsing job code
                logger.critical("Could not parse job id following qsub...")
        return SubmitResults(qid=queue_id, out=out, err=err, process=process)