breaking: remove observable pattern, make methods return events directly

src/main/java/uulm/teamname/marvelous/gamelibrary/entities/NPC.java

@@ -64,4 +64,13 @@ public class NPC extends Entity {
         }
         return clone;
     }
+
+    @Override
+    public String toString() {
+        return "NPC{" +
+                "mp=" + mp +
+                ", inventory=" + inventory +
+                ", position=" + position +
+                '}';
+    }
 }