Test top-to-bottom: object-store containers

Replicate the object-store container command tests but use requests_mock
to test the entire stack down to the requests module.

These will be useful regressions tests when the existing object-store lib
modules are moved to the low-level API object.

Change-Id: Ibf25be46156eb1009f1b66f02f2073d3913b846d
object all tests

Change-Id: Ib1b8ec5fd1696414c11582a9ca107f5e30584099
Add low-level API base class

Adds the foundation of a low-level REST API client.  This is the final prep
stage in the conversion of the object-store commands from the old restapi
interface to the keystoneclient.session-based API.

* api.api.BaseAPI holds the common operations

Change-Id: I8fba980e3eb2d787344f766507a9d0dae49dcadf
Add functional tests to osc

Create a script that kicks off function tests that exercise
openstackclient commands against a cloud.

If no keystone/openstack process is detected, a devstack instance
is spun up and the tests are run against that.

There is also a hook added to tox.ini so that we can run these
tests easily from a gate job.

Change-Id: I3cc8b2b800de7ca74af506d2c7e8ee481fa985f0
Merge branch 'obj-test-end-to-end' into dt-test
Merge branch 'll-api-baseapi' into dt-test