Store and restore Sonja's inventory

[tdauth]

It will only work if both are valid or we use an array with slots and item types to store it.
If only constants are allowed as array indices, it will be a long function.

Clear the inventory of the new Sonja:

func void Npc_ClearInventory(var instance n0)

Go through all items of the old Sonja with:

 int Npc_GetInvItemBySlot(var c_npc self, var int category, var int slotnr)

It returns the number of charges.
Use the global variable item to get the type.
Call this to add it the new Sonja:

func void CreateInvItems(var c_npc n0, var int n1, var int n2)