vCloud version API 1.5 requires us to adapt certain calls. This
patch does all the necessary things to scan a vCloud 1.5 completely
and read all the necessary attributes, as we could already before.
Furthermore, it add tests for the version 1.5 calls.
The API version can now be set as a version param to the vcloud
compute resource. By default it chooses version 1.5.
This has been tested against a vCloud 1.5 and 1.0.
