Releasing beta version for changes to modules API.

This release adds Admin API implementation to modules API. All the modules APIs have an admin API implementation where instead of making a call to appserver, direct call is made to admin API. The appserver implementation still exists and customers can toggle the usage between the two implementations by setting an environment variable in their applications app.yaml.
To opt in for the admin API implementation, customers can add the following to their application's app.yaml :

env_variables:
  APPENGINE_MODULES_USE_ADMIN_API: "true"

Key Features:

• Admin API implementation: Added admin API implementations for all modules APIs. Customers can opt in to these implementations using APPENGINE_MODULES_USE_ADMIN_API environment variable. Customers do not need to make any changes in the way they call these modules APIs.