Support 'Domainname' in container creation
Use different requirements list on Python 2 and 3

In Python 3 websocker-client not required (and previously requiested
version doesn't work at all).
Merge pull request #172 from jdeppe-pivotal/master

Support 'Domainname' in container creation
Merge pull request #178 from rutsky/disable-websocker-on-py3

Use different requirements list on Python 2 and 3 (fixes #174)
Fix API version comparison
fix compare results semantics
remove reference to uninitialized variable and extra parameter in function call