Several API fixes and improvements

* Rename API route names so they use a consistent naming style (api-container, api-container-detail, api-token, api-token-detail)
* Rename API view methods as well, so they use a consistent naming style too
* Raise HTTP 501 not implemented for API methods not yet implemented but probably will be needed later.
* API view class constructor now sets up it's own logger
* Added workaround to production.ini and development.ini for double Gunicorn logger messages when Gunicorn is booting workers.  I believe in newer versions of Gunicorn this is fixed and is no longer needed, but we are using Gunicorn 17.5 from Ubuntu 14.04 LTS for the time being.
* Fix wrong HTTP method POST was used for container action (start/stop/freeze), changed to PATCH which is probably a bit more appropriate for a custom restful API action.
* Fix wrong HTTP method PUT was used for creating containers, changed to POST

Closes #28