
There should only be one way of running tcup. To make it clear to users that might attempt directly running the Docker image, that they must use tcup.py, print the documentation to those users via STDOUT. It also ensures that users get the correct documentation for running their version of the tcup image. Change-Id: Id18f1316c5d7ee4f64c0c2c1c6a32cfc6b648b35