new required role methods get_scheduler_id(), command_status() and run_time(); role also gets helper method _job_name()
ensure_running() reimplemented to rely on Scheduler more - just calls new command_status() method, and get_sid if necessary: we are back to using job arrays
new schema version; no more Runner or SubmissionQueue classes; new SidToSub class that allows server to assign submissions to processes currently running on the compute farm
commit fix
instead of building a SubmissionQueue, now assigns submissions to SidToSubs that were created when a submission handler started running on a compute node: we now know which scheduler id corresponds to which submission id!
submissions mode now only requires -r and -s; submission handling reimplemented to use SidToSubs: now it creates one, waits for a submission to be assigned to it, then it runs it; no longer tries to kill a job if job start_time not found