Dev worker fixes
Ref #505
This fixes a bug whereby timed out jobs could be picked up by another worker, when the current one is in the process of closing.
One has to add in the [worker] section this setting:
# delay after reading the job, should prevent overlaps for multiple workers
additional_delay_after_read = 15(15 seconds is ok, I think even 5 seconds would do).
Also, the js_job_timeout and js_id_timeout settings in TOML file are removed, they weren't used anyways, you can clean them up from the TOML file.