whois.godaddy.com

* Added some date fields support back to Godaddy. 
* The spec file was expecting for wrong value: the Registrar URL should be **http://www.godaddy.com** instead of **http://www.godaddy.com**. This can be confirmed by looking at `spec/fixtures/responses/whois.godaddy.com/status_registered.txt`

```
$ grep URL spec/fixtures/responses/whois.godaddy.com/status_registered.txt
Registrar URL: http://www.godaddy.com
```
* IMO I don't think hard-coding the Registrar URL in this case is good so I changed it. You might have different opinion though.