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/GameState.java

@@ -60,6 +60,10 @@ public class GameState {
         yachts.put(sourceId, yacht);
     }
 
+    public static void removeYacht(Integer yachtId) {
+        yachts.remove(yachtId);
+    }
+
     public static Boolean getIsRaceStarted() {
         return isRaceStarted;
     }