fix Fix Equip Unique Items from Same Giftbox

[Endymion 399]

If we have giftbox from which we can get unique items (ex. Crescent Moon Ring and Thief Glove) we can't equip them both because they have same special group.

bool CItem::IsSameSpecialGroup(const LPITEM item) const
{
	if (this->GetVnum() == item->GetVnum())
		return true;

	if (GetSpecialGroup() && (item->GetSpecialGroup() == GetSpecialGroup()))
		return true;

	return false;
}

into

bool CItem::IsSameSpecialGroup(const LPITEM item) const
{
	if (this->GetVnum() == item->GetVnum())
		return true;

	if (GetSpecialGroup() && (item->GetSpecialGroup() == GetSpecialGroup())){
		TItemTable * p = ITEM_MANAGER::instance().GetTable(GetSpecialGroup());
		if (!p)
			return true;

		if (p->bType != ITEM_GIFTBOX)
			return true;
	}

	return false;
}