Implement a floating action button in fn

sky/examples/stocks-fn/stocksapp.dart

 library stocksapp;
 
 import '../fn/lib/fn.dart';
 import '../fn/widgets/widgets.dart';
 import 'dart:collection';
 import 'dart:math';
 import 'dart:sky' as sky;
 
 part 'companylist.dart';
 part 'stockarrow.dart';
@@ skipping 74 matching lines @@
         ),
         new Icon(key: 'search', style: _iconStyle,
             size: 24,
             type: 'action/search_white'),
         new Icon(key: 'more_white', style: _iconStyle,
             size: 24,
             type: 'navigation/more_vert_white')
       ]
     );
 
+    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,
+      ]
     );
   }
 }