No changes to logic

Improve sched/backfill support for job features, especially XOR construct.
bug 1865

Bug 1973

in the plugins.

when a user doesn't exist in the database.

manager.

Squeue recombines pending job array records only if their name and partition
    are identical.
bug 2057

AllocTRES and ReqTRES are the real mccoys.

Job array termination status email ExitCode based upon highest exit code
    from any task in the job array rather than the last task.
bug 2058

3 problems addressed:
priority/basic does not currently support some functionality
a test was assuming more than one node when submitting two jobs with the --exclusive optiion
a sleep was required so that completing jobs could be cleaned up before submitting a subsequent
  job with the --immediate option

Avoid having stray slurm-#.out file that is difficult to identify
the source of

Based upon patch from Hongjia Cao
bug 2054

Conflicts:
	META
	NEWS

Failed because I had JobRequeue=0 in my slurm.conf

bug 1370

as it is the only TRES that can be given to another job while suspended.

Added test to check that there are at least 2 nodes in
 configuration. Indeed this test seems to expect that there are at list 2
 machines in the hostlist returned by sinfo.

see bug 2050