Initial tabpanel for favorites/history.

template/app/view/Viewport.js

@@ -78,6 +78,15 @@ Ext.define('Docs.view.Viewport', {
                             }
                         ]
                     },
+                    {
+                        xtype: 'tabpanel',
+                        height: 100,
+                        plain: true,
+                        items: [
+                            {title: 'Favorites'},
+                            {title: 'History'}
+                        ]
+                    },
                     {
                         flex: 1,
                         xtype: 'classtree',