Initial commit of YoUltraDNS client implementation.

It's not Demands-based so far, but this is my working version of UltraDNS client, which I use for Domainservice refactoring.
I realize it's not perfect, and comments are very appreciated. I don't promise do fix them quickly, because this ticket is urgent, and it's important to complete this work till 1th Sept, but I plan to refactor it later if required.

Usage:
=====

```
from youltradns import UltraDNSClient
client = UltraDNSClient(settings.NEUSTAR_USERNAME, settings.NEUSTAR_PASSWORD)
client.create_zone('myzone.com')
```
That's very interesting question, which I asked myself many times! And current design is a result of long internal discussions.
Well. We can throw this facade (actually this is a facade). But if so, we'll have to have REST-related code in common client, which violates all OOD rules.