Implement a floating action button in fn

sky/examples/stocks-fn/stocksapp.dart

Index: sky/examples/stocks-fn/stocksapp.dart
diff --git a/sky/examples/stocks-fn/stocksapp.dart b/sky/examples/stocks-fn/stocksapp.dart
index c9ec0359ab567e028929cfe9d8aa6553a66ede16..9bb0638b647f84898dca7caa5cbca0b118180baa 100644
--- a/sky/examples/stocks-fn/stocksapp.dart
+++ b/sky/examples/stocks-fn/stocksapp.dart
@@ -92,10 +92,19 @@ class StocksApp extends App {
       ]
     );
 
+    var fab = new FloatingActionButton(content: new Text('+'));
+
     return new Container(
       key: 'StocksApp',
-      style: _style,
-      children: [drawer, toolbar, new Stocklist(stocks: oracle.stocks)]
+      children: [
+        new Container(
+          key: 'Content',
+          style: _style,
+          children: [toolbar, new Stocklist(stocks: oracle.stocks)]
+        ),
+        fab,
+        drawer,
+      ]
     );
   }
 }