Release/4.0

This is my first attempt at a pull request and I'm sure it's messed up.  There are changes here that I didn't make so it must have something to do with the order of operations in switching branches and pulling from the remote branch that I did.  The salient changes are in work_queue/src/slurm_submit_workers (new file) and work_queue/src/Makefile.  Sorry for the confusion but I wanted to get this out to you.