Replace SchedulerParameters option assoc_limit_continue

Remove the SchedulerParameters option of "assoc_limit_continue", making it
    the default value. Add option of "assoc_limit_stop". If "assoc_limit_stop"
    is set and a job cannot start due to association limits, then do not attempt
    to initiate any lower priority jobs in that partition. Setting this can
    decrease system throughput and utlization, but avoid potentially starving
    larger jobs by preventing them from launching indefinitely.