Inventory - recognize batches of items

[JaXt0r]

In G1 you can drop x amount of an item onto the surface (e.g. 13 ore) and it will only show one mesh. We need to recognize the stack size of a mesh when put into inventory (merge with existing) and put out of inventory.

TODOs:

• Store amount of items
  • retrieve it from ZenKit when Vob is loaded (Open point. Will be solved via Item.cs needs to include "amount" GothicKit/ZenKitCS#7)
  • as Component on the mesh object
• (bonus) When Item is put into inventory, it should merge with the existing items (e.g. 2 in inventory + 3 put into inventory = 5 items but only one inventory slot used)