sshlockout - Add sshlockout utility

sshlockout - Add sshlockout utility

* Add sshlockout utility, typically setup as a syslog pipe.  This utility
  monitors for failed ssh login attempts and excessive preauth failures
  and will add a rule via IPFW to block the originating IP.

  The operator also typically sets up a cron job to clean out the IPFW rules
  that have accumulated once a day.

* See man page for details.  Still under construction (feel free to submit
  additional features).

  TODO - IPV6

  TODO - Use a PF table instead of IPFW, which will greatly improve
	 performance if a lot of rules have to be added.