Change hyperlinks to github.com/henrikingo/impress.js back to upstream repo

examples/2D-navigation/index.html

@@ -27,7 +27,7 @@
 
         <ul>
         <li>Impress.js allows you to layout your presentation in a 3D space</li>
-        <li>Now <a href="https://github.com/henrikingo/impress.js/tree/myfork/src/plugins/goto">the
+        <li>Now <a href="https://github.com/impress/impress.js/tree/master/src/plugins/goto">the
            goto plugin</a> also allows you to specify
            non-linear navigation!</li>
         <li>This demo can be navigated by