Update of openstackcli common and nova components.

 * Added support for the following nova commands to
   the nova client:
     boot, show, list, delete, image-list,
     image-show, image-create, flavor-list,
     flavor-show, volume-attach, volume-create,
     volume-delete, volume-detach, volume-show,
     volume-snapshot-create, volume-snapshot-delete,
     volume-snapshot-list, volume-snapshot-show,
     volume-type-create, volume-type-delete,
     volume-type-list, image-delete.
 * Base response model now properly pulls out the
   pretty table even if it's not at the start of
   stdout.
 * Added response models and extension support for
   all existing and new nova client methods.
 * Added a novacli composite.
 * Added environment variable dictionary support to
   the nova client config.
 * Added new 'Simple' base response models to
   cover deserialization of the most common pretty
   table type.
 * Added new unified response extension base class,
   deprecating the old one.
 * Fixes docstring and comment spacing.

Change-Id: I8183a0b8f502496af50eb06d3896cb9ac325ef0e
Merge "Update of openstackcli common and nova components."