vCloud has also the concept of links in the responses. So we should
make use of them to navigate through the tree of resources in the
vCloud.
Furthermore, we can make various calls a bit easier by directly
returning the specific resource object than the plain xml response.
Adjust tests to work with the new changes, and also test the added
parts.
Improve the models to work with the current api version. add tests
that use fake-data, that was captured from a real vCloud.
Also removed a couple of dead code. Tests have been added for
everything that changed or have been added. All the existing but
untouched parts have not been tested.
