Make isUtc a getter, change some method names in Date.

samples/ui_lib/touch/TimeUtil.dart

 // Copyright (c) 2011, 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.
 
 /**
  * Convenience methods for dealing with time.
  * In the future this could also provide an entry point to mock out time
  * calulation for tests.
  */
 class TimeUtil {
   static int now() {
-    return new Date.now().value;
+    return new Date.now().millisecondsSinceEpoch;
   }
 }