Make tests quieter

* Transition::Import was quite noisy, printing as it did to $stderr a lot
* Add a global #active= to allow printing of messages to null console
* Remove unused option to print anywhere else but $stderr
* Add #console_puts and #console_prints to route these messages through
* extend class-method using import classes to use these. Don't use
  any raw puts/print
Merge pull request #366 from alphagov/quieter-tests

Make tests quieter