Add a basic class to represent ships.
Rewrite the GW test class so it uses the ship object.
Remove the odd exceptions to the GW alternate numbering scheme which
were based on false assumptions.
Improve the GW test code making it much easier to add new MMSI test
cases and look at the programs outputs.
Add further MMSI test cases sent by Alan W.
Add flag , imo and callsign as members of the ship class.
Add further MMSI test cases.
Improve the decoding of MMSIs in 2/101 packets.
Identify as build 62.
Add a comment to the test case to show I know that it fails.
Update the README for build 62.