* Workers now listen to external commands via pubsub. The first two features taking advantage of this infrastructure are `send_shutdown_command()` and `send_kill_horse_command()`. Thanks selwin!
* Added `job.last_heartbeat` property that's periodically updated when job is running. Thanks theambient!
* Now horses are killed by their parent group. This helps in cleanly killing all related processes if job uses multiprocessing. Thanks theambient!
* Fixed scheduler usage with Redis connections that uses custom parser classes. Thanks selwin!
* Scheduler now enqueue jobs in batches to prevent lock timeouts. Thanks nikkonrom!
* Scheduler now follows RQ worker's logging configuration. Thanks christopher-dG!