[Quest API] Adds new methods to NPCs and Corpses (#1510)

- Add $npc->HasItem(item_id) to Perl.
- Add $npc->CountItem(item_id) to Perl.
- Add $npc->GetItemIDBySlot(loot_slot) to Perl.
- Add $npc->GetFirstSlotByItemID(item_id) to Perl.
- Add $corpse->HasItem(item_id) to Perl.
- Add $corpse->CountItem(item_id) to Perl.
- Add $corpse->GetItemIDBySlot(loot_slot) to Perl.
- Add $corpse->GetFirstSlotByItemID(item_id) to Perl.
- Add npc:HasItem(item_id) to Lua.
- Add npc:CountItem(item_id) to Lua.
- Add npc:GetItemIDBySlot(loot_slot) to Lua.
- Add npc:GetFirstSlotByItemID(item_id) to Lua.
- Add corpse:HasItem(item_id) to Lua.
- Add corpse:CountItem(item_id) to Lua.
- Add corpse:GetItemIDBySlot(loot_slot) to Lua.
- Add corpse:GetFirstSlotByItemID(item_id) to Lua.

These methods will allow server operators to view the loot a current has in a slot, the first slot found by item ID, count the item by ID, and see if the NPC has the item.

With that functionality you could build a custom loot system and modify loot more dynamically.

zone/lua_npc.h

@@ -140,6 +140,10 @@ public:
 	bool IsRaidTarget();
 	void ChangeLastName(const char *lastname);
 	void ClearLastName();
+	bool HasItem(uint32 item_id);
+	uint16 CountItem(uint32 item_id);
+	uint32 GetItemIDBySlot(uint16 slot_id);
+	uint16 GetFirstSlotByItemID(uint32 item_id);
 };
 
 #endif