Allow attaching custom config to an abstract queued job.
Allow attaching custom config to an abstract queued job.

nyeholt/silverstripe-queuedjobs,mattclegg/silverstripe-queuedjobs,open-sausages/silverstripe-queuedjobs,souldigital/silverstripe-queuedjobs,andrewandante/silverstripe-queuedjobs,nyeholt/silverstripe-queuedjobs,silverstripe-australia/silverstripe-queuedjobs,andrewandante/silverstripe-queuedjobs,mattclegg/silverstripe-queuedjobs,silverstripe-australia/silverstripe-queuedjobs,open-sausages/silverstripe-queuedjobs,souldigital/silverstripe-queuedjobs