doc(overview): add link to angular demo slides to overview

Author: petebacondarwin

docs/content/guide/overview.ngdoc

@@ -202,6 +202,6 @@ Angular frees you from the following pain:
 
 # Watch a Presentation About Angular
 
-Here is a presentation on Angular from May 2012.
+Here is a presentation on Angular from May 2012. The {@link http://mhevery.github.io/angular-demo-slides/index.html#/list corresponding slides} are also available.
 
 <iframe width="560" height="315" src="http://www.youtube.com/embed/bfrn5VNpwsg" frameborder="0" allowfullscreen></iframe>