Test Discovery.ipaddress & labeled private network support

We discovered that we could drive trucks through this thing.

![work 6176854 1 mtd 375x360 n s vglnahqgu3f1zwv6zq ffffff](https://cloud.githubusercontent.com/assets/149630/3391126/fb26d552-fca6-11e3-8cbb-8da6d14a9d02.jpg)

Added labeled private network support, eg.

``` ruby
local_ipv4 = Discovery.ipaddress(
  :remote_node => remote_node,
  :node => node,
  :type => :label,
  :label => "private"
)
```