added class BattleshipServer, ReceivedMessage to implement the feature that a client is able to start an server edited NetworkDialog to implement the logic to start an server and overhauled the GUI to be appropriate for the new features
added class BattleshipServer, ReceivedMessage to implement the feature that a client is able to start an server edited NetworkDialog to implement the logic to start an server and overhauled the GUI to be appropriate for the new features