Update project authors statements to Dartino

tests/pkg/os/sleep_test.dart

-// Copyright (c) 2014, the Fletch project authors. Please see the AUTHORS file
+// Copyright (c) 2014, the Dartino 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.md file.
 
 import 'package:expect/expect.dart';
 import 'package:os/os.dart' as os;
 
 void main() {
   // Sleep 200 ms.
   int ms = 200;
   Stopwatch stopwatch = new Stopwatch()..start();
   os.sleep(ms);
   // There is a chance that it'll resume slightly early on some system, so we
   // just ensure that at least 50% of the time is spent sleeping.
   int elapsed = stopwatch.elapsedMilliseconds;
   Expect.isTrue(elapsed >= ms ~/ 2, "$elapsed >= ${ms ~/ 2}");
 }