Prepare pubspec/CHANGELOG for version 0.1.2

lib/service_scope.dart

Index: lib/service_scope.dart
diff --git a/lib/service_scope.dart b/lib/service_scope.dart
index 986af1d3d1a2a5622510a7d62848e718edae3c48..856365c77de4b7f1164857e86dd51c56bb6eac7a 100644
--- a/lib/service_scope.dart
+++ b/lib/service_scope.dart
@@ -63,6 +63,15 @@
 ///         print('Server application shut down cleanly');
 ///       });
 ///     }
+///
+/// As an example, the `package:appengine/appengine.dart` package runs request
+/// handlers inside a service scope, which has most `package:gcloud` services
+/// registered.
+///
+/// The core application code can then be independent of `package:appengine`
+/// and instead depend only on the services needed (e.g.
+/// `package:gcloud/storage.dart`) by using getters in the service library (e.g.
+/// the `storageService`) which are implemented with service scope lookups.
 library gcloud.service_scope;
 
 import 'dart:async';