update the fluid examples to use new classes and clear the floats properly from sidebar

docs/upgrading.html

@@ -102,6 +102,11 @@
       <li>Added button bar options</li>
     </ul>
   </li>
+  <li>Examples
+    <ul>
+      <li>Fluid examples redone. <code>.fluid-container</code> now requires a <code>.sidebar-left</code> or <code>.sidebar-right</code> as well. Fluid sidebar element has a new class, <code>.fluid-sidebar</code>.</li>
+    </ul>
+  </li>
 </ul>
 <!--
   <li>