Minor changes to the dart:io library files.

runtime/bin/directory.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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.
 
+/**
+ * [Directory] objects are used for working with directories.
+ */
 interface Directory default _Directory {
   /**
    * Creates a directory object. The path is either a full path or
    * relative to the directory in which the Dart VM was
    * started.
    */
   Directory(String path);
 
   /**
    * Check whether a directory with this name already exists. If the
@@ skipping 122 matching lines @@
   final String path;
 }
 
 
 class DirectoryException {
   const DirectoryException([String this.message, int this.errorCode = 0]);
   String toString() => "DirectoryException: $message";
   final String message;
   final int errorCode;
 }