Way better overall.  Many bugs removed, including some really bad ones.
Added a few improvements, including the ability to drag job off of queue to delete.
Deal with empty queue by inserting placeholder and check last XP by default.
Merge remote-tracking branch 'origin/major_rewrite_for_piside_job_queue' into major_rewrite_for_piside_job_queue
Extra logging and more robust abort_all pi-side.
Fixed bug with job deletion not being pushed to pi properly.
Added clear_queue button.