Make stocksapp.dart almost pass the dart analyzer.

sky/examples/stocks-fn/stocksapp.dart

 library stocksapp;
 
 import '../../framework/fn.dart';
 import '../data/stocks.dart';
 import '../fn/widgets/widgets.dart';
-import 'dart:collection';
 import 'dart:math';
-import 'dart:sky' as sky;
 
 part 'stockarrow.dart';
 part 'stocklist.dart';
 part 'stockrow.dart';
 
 class StocksApp extends App {
 
   DrawerAnimation _drawerAnimation = new DrawerAnimation();
 
   static Style _style = new Style('''
@@ skipping 77 matching lines @@
           key: 'Content',
           style: _style,
           children: [toolbar, new Stocklist(stocks: oracle.stocks)]
         ),
         fab,
         drawer,
       ]
     );
   }
 }