findIp() without container object

[schnatterer]

Make findIp() also run with a container ID String instead of a container Object.

e.g. overloaded (if possible)

• String findIp(String containerId)
• String findIp(container)

Or duck typed, if String use as ID, otherwise fall back to container.id.

[schnatterer]

Another nice extension:

findNetwork()

docker inspect -f '{{range .NetworkSettings.Networks}}{{.NetworkID}}{{end}}' container