[tests] Port unittest_cwctl to py3k
On python 2, sys.stdout takes bytes-like objects whereas python 3's
takes unicode-like objects and handles the encoding on its own.
===================
Changelog history
===================
.. include:: 3.21.rst
.. include:: 3.20.rst
.. include:: 3.19.rst
.. include:: 3.18.rst
.. include:: 3.17.rst
.. include:: 3.16.rst
.. include:: 3.15.rst
.. include:: 3.14.rst