Improve handling of job updates when using limits in accounting, and updating jobs as a non-admin user.

actual and configured values 

was going through re-size logic instead of just returning OK for no-op

This prevents preserving PreemptMode from an old slurm.conf after a reconfig

Clear pending job's start_time between executions of sched/backfill.

Fix for sview started on a non-bluegene system to pick colors correctly when talking to a real bluegene system.

    Use PREFIX instead to avoid build errors from multiple installation
    specifications.

    a full midplane on BlueGene computers. Treat cnodes as liceses which can
    be reserved and are consumed by jobs.

    Perl can not build if both are set.

    step names, and account names with an underscore to insure proper parsing.

BLUEGENE - Fix for handling extremely overloaded system on Dynamic system dealing with starting jobs on overlapping blocks.  Previous fallout was job would be requeued.  (happens very rarely)

    "%j" in the job's output or error file specification.

BLUEGENE - If using OVERLAP mode fixed issue with jobs getting denied at submit if the only option for their job was overlapping a block in error state.

    the slurmd daemon(s). This insures that tasks in the process of getting
    spawned are killed.

    having a job start that runs into the reservation when later advanced.

and explain the change in job allocation man pages

   sockets option" behavior.

   affinity with plane distribution" bug.

Gerrit Renker:  I found an easier test: after making sure that stdin is not
 redirected, check whether there is a non-negative terminal process group (it
 is -1 if there is no controlling terminal).

 Also, I think that the heuristic "only interactive if from login shell" is
 needlessly complicated/obscure. Most (if not all) shells that support job
 control place processes in their own process group (pid == pgrp): it now uses
 this as indicator of interactive mode.

The following tests now pass:

  salloc &			# from login shell and from nested shell
  salloc --no-shell&		# ok
  salloc /bin/date&		# wants to be placed into the foreground
  salloc /bin/date </dev/null &	# ok

  setsid salloc	 		# complains there is no controlling terminal
  setsid salloc --no-shell&	# ok