/// <summary>
/// Adds an item to the map. This is the final step in the Add() method of an item
/// and should not be called on its own.
/// </summary>
/// <param name="item">The item.</param>
/// <param name="mainNode">The main node of the item. This will determine which sector
/// contains the item.</param>
void IItemContainer.AddItem(MapItem item)
{
Items.Add(item);
}