Switch pkg packages, pub, and dartdoc to use package: imports.

utils/tests/pub/io_test.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.
 
 library io_test;
 
-import '../../../pkg/pathos/lib/path.dart' as path;
-import '../../../pkg/unittest/lib/unittest.dart';
+import 'package:pathos/path.dart' as path;
+import 'package:unittest/unittest.dart';
 
 import '../../pub/io.dart';
 import '../../pub/utils.dart';
 import 'test_pub.dart';
 
 main() {
   initConfig();
 
   group('listDir', () {
     test('lists a simple directory non-recursively', () {
@@ skipping 109 matching lines @@
         }).then((_) => listDir(temp, recursive: true));
         expect(future, completion(unorderedEquals([
           path.join(temp, 'file1.txt'),
           path.join(temp, 'linkdir')
         ])));
         return future;
       }), completes);
     });
   });
 }