Fixed minor bugs.

These bugs were discovered when looking at the logs and are considered specials cases and non-critical. Changed toString() for Hand.java to return "<empty>" when an instance contains no cards. Changed onMessage() in subclasses of ListenerAdapter to ignore commands that begin with commandChar+" ".
Changes for issue #112.

Added the ability to supply an auto-start parameter to the "go"/"start" command. Updated help files to reflect change.