fixed failing tests

- ShipMapTest: notify ItemRemovedEvent when calling the remove method.
- ClientGame1Player1 and ClientGame2Player2Test: Ensure opponent's is retrieved in game over state.

Projekte/battleship/model/src/main/java/pp/battleship/game/client/BattleState.java

@@ -60,7 +60,7 @@ public void receivedEffect(EffectMessage msg) {
         if (destroyedOpponentShip(msg))
             logic.getOpponentMap().add(msg.getDestroyedShip());
         if (msg.isGameOver()) {
-            msg.getRemainingOpponentShips().forEach(logic.getOwnMap()::add);
+            msg.getRemainingOpponentShips().forEach(logic.getOpponentMap()::add);
             logic.setState(new GameOverState(logic));
         }
     }

Projekte/battleship/model/src/main/java/pp/battleship/model/ShipMap.java

@@ -10,6 +10,7 @@
 import pp.battleship.notification.GameEvent;
 import pp.battleship.notification.GameEventBroker;
 import pp.battleship.notification.ItemAddedEvent;
+import pp.battleship.notification.ItemRemovedEvent;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -97,7 +98,7 @@ public void add(Shot shot) {
      */
     public void remove(Item item) {
         items.remove(item);
-        notifyListeners(new ItemAddedEvent(item, this));
+        notifyListeners(new ItemRemovedEvent(item, this));
     }
 
     /**