Rename fletch -> dartino

tests/coroutine/fiber_join_test.dart

 // 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 'dart:fletch';
+import 'dart:dartino';
 
 import 'package:expect/expect.dart';
 
 main() {
   testResult();
   testExit();
 }
 
 testResult() {
   Expect.equals(42, Fiber.fork(() => 42).join());
@@ skipping 14 matching lines @@
   Expect.equals(87, Fiber.fork(() => Fiber.exit(87)).join());
 
   Function newYielder(value) => () {
     Fiber.yield();
     Fiber.exit(value);
   };
 
   Expect.equals(42, Fiber.fork(newYielder(42)).join());
   Expect.equals(87, Fiber.fork(newYielder(87)).join());
 }