support for specifying local bind address

adds the ability to specify what ip address the container should bind to, eg:
```
docker run -p 127.0.0.1:8080:8080 ...
```
i want to use the plugin to do actual deployments into docker and have a use case where an app needs to listen on a separate interface, so i need to be able to specify an ip.

it also cleans up some compiler warnings and swaps the test ares so they are 'expected/actual' :)