Enforce --ntasks-per-socket=1 job option when allocating by socket

See
https://groups.google.com/forum/#!topic/slurm-devel/j4izr0L4w8w
Add Armin Größlinger to contributor/team list
When a job is requeued reset the step id's back to 0.
remove last comment,  it is documented in job_mgr.c as this...

/* Current code (<= 2.1) has it so we start the new
 * job with the next step id.  This could be used
 * when restarting to figure out which step the
 * previous run of this job stopped on. */
Merge remote-tracking branch 'origin/slurm-2.6'