Don't hardcode the list of events types 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 19 matching lines @@
 
   static Style _titleStyle = new Style('''
     flex: 1;
     margin: 0 4px;'''
   );
 
   StocksApp() : super();
 
   Node render() {
     var drawer = new Drawer(
-      onPositionChanged: _drawerAnimation.onPositionChanged,
-      handleMaskFling: _drawerAnimation.handleFlingStart,
-      handleMaskTap: _drawerAnimation.handleMaskTap,
-      handlePointerCancel: _drawerAnimation.handlePointerCancel,
-      handlePointerDown: _drawerAnimation.handlePointerDown,
-      handlePointerMove: _drawerAnimation.handlePointerMove,
-      handlePointerUp: _drawerAnimation.handlePointerUp,
+      animation: _drawerAnimation,
       children: [
         new DrawerHeader(
           children: [new Text('Stocks')]
         ),
         new MenuItem(
           key: 'Inbox',
           icon: 'content/inbox',
           children: [new Text('Inbox')]
         ),
         new MenuDivider(
@@ skipping 12 matching lines @@
           key: 'Help & Feedback',
           icon: 'action/help',
           children: [new Text('Help & Feedback')]
         )
       ]
     );
 
     var toolbar = new Toolbar(
       children: [
         new Icon(key: 'menu', style: _iconStyle,
-            onClick: _drawerAnimation.toggle,
             size: 24,
-            type: 'navigation/menu_white'),
+            type: 'navigation/menu_white')
+          ..events.listen('click', _drawerAnimation.toggle),
         new Container(
           style: _titleStyle,
           children: [new Text('I am a stocks app')]
         ),
         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')
@@ skipping 10 matching lines @@
           key: 'Content',
           style: _style,
           children: [toolbar, new Stocklist(stocks: oracle.stocks)]
         ),
         fab,
         drawer,
       ]
     );
   }
 }