Menu: Drop contextmenu link from menu demos index, demo doesn't exist

Author: jzaefferer

demos/menu/index.html

@@ -10,7 +10,6 @@
 		<h4>Examples</h4>
 		<ul>
 			<li class="demo-config-on"><a href="default.html">Default functionality</a></li>
-			<li><a href="contextmenu.html">Contextmenu</a></li>
 			<li><a href="topalignmenu.html">Top-aligned sub menus</a></li>
 			<li><a href="navigationmenu.html">Navigation menu</a></li>
 		</ul>