Roll Observatory packages and add a roll script

intl/lib/src/file_data_reader.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 contains a reader that accesses data from local files, so it can't
- * be run in the browser.
- */
-
-library file_data_reader;
-
-import 'dart:async';
-import 'package:path/path.dart';
-import 'dart:io';
-import 'intl_helpers.dart';
-
-class FileDataReader implements LocaleDataReader {
-
-  /// The base path from which we will read data.
-  String path;
-
-  FileDataReader(this.path);
-
-  /// Read the locale data found for [locale] on our [path].
-  Future read(String locale) {
-    var file = new File(join(path, '$locale.json'));
-    return file.readAsString();
-  }
-}