update demo 1

Author: nhancv

lib/main.dart

@@ -1,7 +1,7 @@
 import 'package:flutter/widgets.dart';
 import 'package:flutter/material.dart';
-//import 'demo1.dart';
-import 'demo2.dart';
+import 'demo1.dart';
+//import 'demo2.dart';
 
 void main() => runApp(new MyApp());