SLURM_IMMEDIATE_EXIT to SLURM_EXIT_IMMEDIATE

    to permit user control over exit codes so application exit codes can be
    distiguished from those generated by SLURM. SLURM_ERROR_EXIT specifies the
    exit code when a SLURM error occurs. SLURM_IMMEDIATE_EXIT specifies the 
    exit code when the --immediate option is specified and resources are not
    available. Any other non-zero exit code would be that of the application
    run by SLURM.

env var rather than always being 1. This enables a user to distinguish between
slurm failures and application failures

    of slurmctld rather than that of the command.

    within the job's memory allocation and enforce limits).

    gang scheduling module. Make identification of preemptable jobs an argument
    to the select_g_job_test function rather than calling preempt plugin from
    the select plugin. Make output of srun --test-only option include a list
    of preempted job IDs. 
    svn merge -r18780:18815 https://eris.llnl.gov/svn/slurm/branches/preempt.job.list