Update README file

lib/storage.dart

 // Copyright (c) 2014, 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 library provides access to Google Cloud Storage.
 ///
 /// Google Cloud Storage is an object store for binary objects. Each
 /// object has a set of metadata attached to it. For more information on
 /// Google Cloud Sorage see https://developers.google.com/storage/.
 ///
@@ skipping 59 matching lines @@
 ///
 /// The returned object will be the one which was previously registered with
 /// [registerStorageService] within the current (or a parent) service scope.
 ///
 /// Accessing this getter outside of a service scope will result in an error.
 /// See the `package:gcloud/service_scope.dart` library for more information.
 Storage get storageService => ss.lookup(_storageKey);
 
 /// Registers the [storage] object within the current service scope.
 ///
-/// The provided `storage` object will be avilable via the top-level
+/// The provided `storage` object will be available via the top-level
 /// `storageService` getter.
 ///
 /// Calling this function outside of a service scope will result in an error.
 /// Calling this function more than once inside the same service scope is not
 /// allowed.
 void registerStorageService(Storage storage) {
   ss.register(_storageKey, storage);
 }
 
 int _jenkinsHash(List e) {
@@ skipping 335 matching lines @@
 
   String toString() => 'AclPermission($_id)';
 }
 
 /// Definition of predefined ACLs.
 ///
 /// There is a convenient way of referring to number of _predefined_ ACLs. These
 /// predefined ACLs have explicit names, and can _only_ be used to set an ACL,
 /// when either creating or updating a bucket or object. This set of predefined
 /// ACLs are expanded on the server to their actual list of [AclEntry] objects.
-/// When information is retreived on a bucket or object, this expanded list will
+/// When information is retrieved on a bucket or object, this expanded list will
 /// be present. For a description of these predefined ACLs see:
 /// https://cloud.google.com/storage/docs/accesscontrol#extension.
 class PredefinedAcl {
   final String _name;
   const PredefinedAcl._(this._name);
 
   /// Predefined ACL for the 'authenticated-read' ACL. Applies to both buckets
   /// and objects.
   static const PredefinedAcl authenticatedRead =
       const PredefinedAcl._('authenticatedRead');
@@ skipping 325 matching lines @@
   /// Start paging through objects in the bucket.
   ///
   /// The maximum number of objects in each page is specified in [pageSize].
   ///
   /// See [list] for more information on the other arguments.
   ///
   /// Returns a `Future` which completes with a `Page` object holding the
   /// first page. Use the `Page` object to move to the next page.
   Future<Page<BucketEntry>> page({String prefix, int pageSize: 50});
 }