Fixed issue where assoc_mgr cache wasn't always loaded correctly if the slurmdbd wasn't running when the slurmctld was started.

Fixed issue where if a system has unset messages to the dbd in 2.1 and upgrades to 2.2.  Messages are now processed correctly now.

    minimize lost messages. Effects slurmd epilog complete messages and PMI
    key-pair transmissions. Patch from Gerrit Renker, CSCS.

    when job preemption is configured.

    job_submit and job_modify functions as an error and the user request should
    be treated as an error.

    into an array. Patch from Gerrit Renker, CSCS.

   "FairShare" and added more detail to the sshare man page.

Fix bug where if using the slurmdbd if a job wasn't able to start right away some accounting information may be lost.