WIP: Rackconnect v3 Load Balancer Pool support

This provides API support for RackConnect V3 load balancers.  First task of #104 
Although I don't think we care about py3 yet, it's worth noting that `basestring` is a py2-ism:

```
Python 3.4.2 (default, Oct 19 2014, 17:55:38) 
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.54)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> basestring
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'basestring' is not defined
```