more link tweaking

src/site/docs/tutorials/remove-elements/index.markdown

 ---
 layout: default
 title: "Remove DOM Elements"
 description: "Remove a child element from the DOM"
 has-permalinks: true
 tutorial:
   id: remove-elements
-next: shared-pkgs
+next: shared-pkgs/
 next-title: "Install Shared Packages"
-prev: add-elements
+prev: add-elements/
 prev-title: "Add Elements to the DOM"
 ---
 
 {% capture whats_the_point %}
 
 * Use _element_.remove() to remove an element from the DOM.
 * Remove all children from an element with _element_.children.clear().
 * Function expressions are a convenient way to define single-use functions.
 * => is a shorthand syntax for defining functions that contain just one
 expression.
@@ skipping 47 matching lines @@
 a new item appears in the list.
 Enter a few more items.
 Point the mouse cursor at one of the items in the list;
 the item turns red and gets slightly larger.
 Click it and it disappears from the list.
 Use the **Delete All** button in the lower right corner of the app
 to remove all of the items in the list at once.
 
 <iframe class="running-app-frame"
         style="height:250px;width:300px;"
-        src="http://dart-lang.github.com/dart-tutorials-samples/web/target04/todo_with_delete/web/todo_with_delete.html">
+        src="http://dart-lang.github.io/dart-tutorials-samples/web/target04/todo_with_delete/web/todo_with_delete.html">
 </iframe>
 
 You can find the complete source code for this sample on github at
 <a href="https://github.com/dart-lang/dart-tutorials-samples/tree/master/web/target04/todo_with_delete"
 target="_blank">todo_with_delete</a>.
 
 The remaining sections describe
 key aspects of the code 
 added to the todo app for this target.
 Specifically, they look at
@@ skipping 146 matching lines @@
     You can find more information about the DOM and CSS in
     <a href="/docs/dart-up-and-running/">Dart Up and Running</a>,
     which also provides thorough coverage of the Dart language, 
     libraries, and tools.
   </li>
 </ul>
 
 {% endcapture %}
 
 {% include tutorial.html %}