Enable overrides passing to OZ (memory, cpus, default image)
 which now allows qcow2 to be default image type

* imagefactory
    - qcow2 is now the default output vs raw
    - corrected the parsing of images, streamlined
    - created ImageFunctions class that that enable
      passing of oz override metadata in json
    - by default, we now require:
        - memory > 2047
        - cpus = 2
        - default_image = qcow2

* taskbase
    * minor cleanup to expose the name-release