Make OutbackCDX console output easier to control

[anjackson]

At the time of writing, OutbackCDX writes directly to System.out (see here) - and possibly System.err.

This leads to quite a lot of log output in our use case, which we can control/rotate, but ideally I'd like to be able to configure it via some kind of Java logging library. This issue is a note to remind me of that. Specifically:

• Ask if that would be okay and what logging library would be preferred.
• Submit a PR that makes the changes.