Major redesign: The game can not be left without disconnecting from the server. This happens if a player is kicked, if he wishes to leave, or for other reasons. Error packets from the server will always cause a disconnect, however.

If joining a game fails, there is a proper failure packet now.

src/session.h

@@ -53,6 +53,7 @@ public:
 	void clientJoinGame(unsigned gameId, const std::string &password);
 
 	void startNetworkServer();
+	void sendLeaveCurrentGame();
 	void sendStartEvent(bool fillUpWithCpuPlayers);
 	void terminateNetworkServer();
 	void waitForNetworkServer(unsigned timeoutMsec);