=====
* In ``misc_utils``:
* New decorator ``classproperty``
* New decorator ``classproperty_cached``
* New decorator ``classproperty_cached_each_subclass``
* New class ``Singleton``. Users of ``SingletonManager`` might prefer this,
but we'll continue to support both. (No deprecation for now.)
* In function ``is_valid_absolute_uri``, better handling of argument type errors.
* For ``CachedField``:
* Added a handler for ``__str__`` that returns useful information, which can also be used for ``__repr__``.
* Fixed handler for ``__repr__`` to return a properly executable expression (shared with ``__str__``).
* Improved test coverage by adding tests for some parts of the code that were not previously tested.
* In ``qa_utils``:
* New class ``MockId`` for mocking the ``id`` function in a predictable way.
* Adjust ``MOCK_QUEUE_URL_PREFIX`` to use a mocked URL that looks more
like modern AWS url, where ``queue.amazonaws.com`` has been replaced by
``sqs.us-east-1.amazonaws.com``.