load slideshow by default

IPython/frontend/html/notebook/templates/notebook.html

@@ -225,5 +225,6 @@ data-notebook-id={{notebook_id}}
 <script src="{{ static_url("js/contexthint.js") }}" charset="utf-8"></script>
 
 <script src="{{ static_url("js/celltoolbarpresets/default.js") }}" type="text/javascript" charset="utf-8"></script>
+<script src="{{ static_url("js/celltoolbarpresets/slideshow.js") }}" type="text/javascript" charset="utf-8"></script>
 
 {% endblock %}