added logic for modify job to work correctly on bluegene systems, also added check to make sure limits are abused on a job update

    name of NULL rather than returning no information about the node so that
    node index information is still valid.

    --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).