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

I think @Ichimonji10 wants the first docstring line to be at the top, next to the opening quotes:

```python
"""@test: Enable...
```

Also, an empty line before the closing quotes.