Droppable: Remove shopping cart demo from index it was deleted

Author: arschmitz

demos/droppable/index.html

@@ -13,7 +13,6 @@
 	<li><a href="propagation.html">Prevent propagation</a></li>
 	<li><a href="visual-feedback.html">Visual feedback</a></li>
 	<li><a href="revert.html">Revert draggable position</a></li>
-	<li><a href="shopping-cart.html">Shopping Cart</a></li>
 	<li><a href="photo-manager.html">Simple photo manager</a></li>
 </ul>