implement swift client commands

Swift has no client library in the same manner as the other clients, it does have swiftclient/client.py but also has dependencies that do not fit well with the other libs. Let's re-work that layer to use python-requests and take advantage of some of its capabilities, such as parameter quoting. The SSL-compressions and chunked transfer will take the most work but are also needed for Glance so eventually we'll be going there anyway.

The naming of the functions in client.py are a bit counter-intuitive, as in you call get_accounts to get a list of containers. In the reqork of clients.py the function names will be changed to more closely match our usage and not be a direct mapping of the API being called.

A low-level REAT API layer has been created (openstackclient.common.restapi) that will be used here as well as in the API commands. The object library-layer is located in openstackclient.object.v1.lib while the command objects themselves are in the usual location openstackclient.object.v1.

Gerrit topic: https://review.openstack.org/#q,topic:bp/swift-client,n,z

Addressed by: https://review.openstack.org/111552
    Add container create and delete support

Addressed by: https://review.openstack.org/111557
    Add commands for object upload and delete

Addressed by: https://review.openstack.org/119293
    Add preliminary support for downloading objects

Gerrit topic: https://review.openstack.org/#q,topic:ksc-session,n,z

Addressed by: https://review.openstack.org/119417
    Add preliminary save container support

Work items:
Container and obejct list commands: DONE
Container and obejct show commands: DONE