Pepare for v1.2 release.

Reviewed in https://codereview.appspot.com/10841043/.
diff --git a/CHANGELOG b/CHANGELOG
index 4e2a9eb..7892645 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,29 @@
+v1.2
+  Version 1.2
+
+  The use of the gflags library is now deprecated, and is no longer a
+    dependency. If you are still using the oauth2client.tools.run() function
+    then include gflags as a dependency of your application or switch to
+    oauth2client.tools.run_flow.
+  Samples have been updated to use the new apiclient.sample_tools, and no
+    longer use gflags.
+  Added support for the experimental Object Change Notification, as found in
+    the Cloud Storage API.
+  The oauth2client App Engine decorators are now threadsafe.
+
+  - Use the following redirects feature of httplib2 where it returns the
+    ultimate URL after a series of redirects to avoid multiple hops for every
+    resumable media upload request.
+  - Updated AdSense Management API samples to V1.3
+  - Add option to automatically retry requests.
+  - Ability to list registered keys in multistore_file.
+  - User-agent must contain (gzip).
+  - The 'method' parameter for httplib2 is not positional. This would cause
+    spurious warnings in the logging.
+  - Making OAuth2Decorator more extensible. Fixes Issue 256.
+  - Update AdExchange Buyer API examples to version v1.2.
+
+
 v1.1
   Version 1.1