Docker: Revision 0.3.2 Updates (no interface changes)

    *  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.
    
    *  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.
    
    *  Added missing __init__ method to DockerImagesCLI and
       DockerContainersCLI to fill in default params.
    
    *  Added standard autotest test exceptions to xceptions module.
       This makes it easier for tests (they don't need to import
       big-long autotest module).  It also allows us to see the
       different between a test-raised exception and harness-raised.
    
    *  Extended DockerImagesCLI and DockerContainersCLI
       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.
    
    *  Extended CLI interfaces for images and containers with
       new name 'clic'.  This is for when the image or ps command
       is the test subject and therefor output checkers need to
       run against it's output.
    
    *  Added annother output module 'checker' to watch for an
       'error: ' string in output.  Updated all negative subtests
       to properly invert the checker results.
    
    *  Updated build subtest to log a message when postprocess
       failed to remove the built image.
    
    *  Added output_check method and override to pull tests.
       Updated negative subsubtest 'wrong_registry_addr' to properly
       fail on SUCCESSFUL checks (error-check now catches here)
    
    *  Updated run subtest to use utils.signal_pid() which has some
       extra testing-related checks involved.
    
    *  Added additional verbosity to check in version subtest.