rabbitmq container output changed and admin password can no longer be determined
First container starts are broken

The output is different when containers have to be downloaded
and thus container IDs cannot be determined. This is a change
that came with the Docker upgrade to 1.3.

Also, Docker output should be forwarded to the user. Swallowing
the output results in a bad user experience because the user
is not informed about image downloads.

Fixes #6 and #8