--sockets-per-node, --cores-per-socket and --threads-per-core options.
    Remove --mincores, --minsockets, --minthreads options (map them to 
    minimum values of -sockets-per-node, --cores-per-socket and 
    --threads-per-core for now).

do some general clean up of the web page.

in the wiki2 interface, we'll go with one job at a time and a list of preemption
candates and preempted jobs returned instead

    preemptable and preempted jobs (both new and old format of commands are
    supported).

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