Docker: Add helpers for docker container operations

*  Bumped revision number to 0.3.2

*  Cleaned up some minor pylint problems

*  Added an 's' on the end of images_unittest.py

*  Added simple unittests script to execute them
   all in parallel.

*  Updated documentation to include subtest.SubSubtestCaller
   class.  It was mistakenly not added previously.

*  Added minimal networking module with ContainerPort class.
   Follows very closely to the same pattern as images module.
   TODO: Update Docs

*  Added minimal containers module also mirroring closely
   with the images pattern.  However there are quite a few
   more container attributes, only some are needed for
   creation, the rest are simply stuck onto the class.
   TODO: Add removal methods
   TODO: Update Docs

*  Added __init__ method to DockerImagesCLI to fill in
   default params.

*  Extended DockerImagesCLI interface by turning
   docker_cmd() into a public method.  This allows
   the possibility for tests to perform checks or
   modifications when the command being used is
   the subject of a test.  Changed the timeout
   parameter to be non-defaulting.  Callers
   may override this behavior if needed.

Signed-off-by: Chris Evich <cevich@redhat.com>
Docker: Add test for 'ps -a' subcommand

Signed-off-by: Chris Evich <cevich@redhat.com>