Enhancements

- Support for the skynet c2020 cluster,
- qstatus.py uses cherrypy to display all the queues in a web-page,
- Added the queue_all command, to print out all jobs from a given cluster,
- Support for the arcus-gpu k20 slurm cluster,
- Job duration is now a command-line argument (defalt "24:00:00", or 24h)