Implemented Repository Sets in CLI

Added test for subscribtions.

Requires manifest containing specific repository to work, in this case:
'Red Hat Enterprise Virtualization Agents for RHEL 6 Workstation RPMs x86_64 6Workstation'

Works with this manifest:

http://pastebin.test.redhat.com/231686

Aye. My personal preference is to write docstrings like this:

```python
def test_foo(self):
    """@Test: Frobnigate the foo until the fiz bams.

    @Feature: foo

    @Assert: The fiz bammed.

    """
    pass
```