Add async initialization for Intl.message and an example

pkg/intl/example/basic/basic_example_shell.dart

+// 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.
+
+/**
+ * This is just a shell that runs the code in basic_example.dart, leaving

[Emily Fortuna, 2012/09/12 01:23:48]

I'd rename this file to something like basic_example_runner.dart or
basic_example_main.dart. I first opened the basic_example.dart file and was
confused how it got called, and I think making this file be the more
straightforward "look at me first" name will fix that.

[Alan Knight, 2012/09/12 20:58:20]

Done.

+ * that as a library that can also be run by tests.
+ */
+
+#import('basic_example.dart');
+
+main() {
+  setup(runProgram, print);
+}