Openstack Python CLI buildout

* Adds openstackcli package
* Adds common and cindercli subpackages for openstackcli
* Adds base model for parsing the prettytable that gets printed
  by the various openstack CLI's
* Adds a base client for interfacing with the openstack CLI's
* Implements a cinder CLi client and model with support for the
  create, delete, list, and type-list commands.

Change-Id: I032a026d9f07b44b0065355cdac29a319e1bb183
Merge "Openstack Python CLI buildout"