Add client to talk to RackConnect api

This patch adds a client to talk with the rackconnect api.
Currently, it only deals with adding/removing dedicated
loadbalancers and assigning/removing public IP's to
cloudservers. These are the only services which are 
currently (at the time of this PR) exposed via the 
rackconnect api: http://docs.rcv3.apiary.io/
If I change 174-175 to:
```python
# occasionally, its just a list (rackconnect for example)
if isinstance(resp_body, list):
    return resp_body
```
Then everything works again.