moving the inventory from LivingEntity to Player

modified:   src/entity/EntityManager.java
modified:   src/entity/LivingEntity.java
modified:   src/entity/npc/Npc.java
modified:   src/entity/npc/Zombie.java
modified:   src/entity/player/Player.java
modified:   src/game/GameLoop.java
modified:   src/userInterface/OverlayManager.java
modified:   src/userInterface/inventory/Inventory.java