code: protected Node removeNode( Node node )
      {
          // Remove node.
          node.previous.next = node.next;
          node.next.previous = node.previous;
          node.removed = true;
          return node;
      }
docs: Removes the specified node from the list.
  
  @param node  the node to remove
  @throws NullPointerException if <code>node</code> is null