Added a -recover option (e.g. pktdump -r *.pkt). This option will create
duplicates of all the parsed packet files, but excluding all corrupted packed messages. The recovered packet files are named *.recovered. Also improved the corrupted packed message header detection to make this feature more useful. Created at the request of Nelgin who promises to test and use, for better or for worse, in sickness and in health, from this day forward, yadda yadda yadda.