Change the name of Component.render to Component.build in Effen

sky/examples/fn/widgets/box.dart

 part of widgets;
 
 class Box extends Component {
 
   static Style _style = new Style('''
     display: flex;
     flex-direction: column;
     border-radius: 4px;
     border: 1px solid gray;
     margin: 10px;'''
   );
 
   static Style _titleStyle = new Style('''
     flex: 1;
     text-align: center;
     font-size: 10px;
     padding: 8px 8px 4px 8px;'''
   );
 
   static Style _contentStyle = new Style('''
     flex: 1;
     padding: 4px 8px 8px 8px;'''
   );
 
   String title;
   List<Node> children;
 
   Box({String key, this.title, this.children }) : super(key: key);
 
-  Node render() {
+  Node build() {
     return new Container(
       style: _style,
       children: [
         new Container(
           key: 'Title',
           style: _titleStyle,
           children: [new Text(title)]
         ),
         new Container(
           key: 'Content',
           style: _contentStyle,
           children: children
         ),
       ]
     );
   }
 }