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')
```
Names doesn't matter in our case.
We have what you've just said - Client (UltraDNSClient) calls RestAPIClient (UltraDNSRestAPI). Names are different, but the idea is same.
The Stefano's concern (and my concern too) is that the Client is suspiciously thin.