renamed less.html to extend.html, removing all the vars and mixins

docs/javascript.html

@@ -57,9 +57,6 @@
               <li class="active">
                 <a href="./javascript.html">Javascript</a>
               </li>
-              <li class="">
-                <a href="./less.html">LESS</a>
-              </li>
               <li class="divider-vertical"></li>
               <li class="">
                 <a href="./download.html">Customize</a>
@@ -67,6 +64,9 @@
               <li class="">
                 <a href="./examples.html">Examples</a>
               </li>
+              <li class="">
+                <a href="./extend.html">Extend</a>
+              </li>
             </ul>
           </div>
         </div>