update hello, world sample and remove slider

samples/hi/hi.dart

Index: samples/hi/hi.dart
diff --git a/samples/hi/hi.dart b/samples/hi/hi.dart
index 77cc144f834513f040b0496efde571b3ea84607a..2ce0f41f920cf65027111390b2f071231db16638 100644
--- a/samples/hi/hi.dart
+++ b/samples/hi/hi.dart
@@ -1,11 +1,11 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-#library('hi');
+library hi;
 
-#import('dart:html');
+import 'dart:html';
 
 main() {
-  document.query('#status').innerHTML = 'Hi, Dart';
+  query('#status').text = 'Hi, Dart';
 }