Make it work without a terminal.

Thanks to RKD and http://www.continuous-qa.com/2013/03/jenkins-error-opening-terminal-unknown.html
Disable colours on request.
Review markups - avoid extra env var.

Just reuse existing TERM - this is set if we have a terminal
(where we already assume ANSI), and not set where we don't.
Merge pull request #4 from Metaswitch/enhance-live-test

[Reviewer: Andy] Enhance live test