Re-add trivial constructor for JujuClient to avoid 'object() takes no parameters' errors
temporarily disable all tests that try to use code that's commented out in juju/client.py, pending websocket python3ification
Add zone_delete function to support cleaning up after tests.
Rework tests to clean up after themselves and to check for the specific created zone/tag.
Merge branch 'master' into test-cleanup
Merge pull request #14 from Ubuntu-Solutions-Engineering/test-cleanup

Test cleanup