Fixed sending wrong race xml when a player disconnected because xml is getting data from gamestate yacht but the yachts are not updated is player disconnect.

Heartbeat packet was sent out at wrong rate which cause the player disconnect detection to be slow. Heartbeat packet is send out every 200ms now.

#story[1055] #pair[hyi25, zyt10]

src/main/java/seng302/gameServer/HeartbeatThread.java

@@ -13,7 +13,7 @@ import java.util.*;
  * cannot be sent to a player
  */
 public class HeartbeatThread extends Thread{
-    private final int HEARTBEAT_PERIOD = 5000;
+    private final int HEARTBEAT_PERIOD = 200;
     private ClientConnectionDelegate delegate;
     private Integer seqNum;
     private Stack<Player> disconnectedPlayers;