Code review comment for lp:~bcsaller/pyjuju/sane_output_test_option

Reviewers: mp+106067_code.launchpad.net,

Message:
Please take a look.

Description:
Adds support for --test and doesn't output Python reprs

This branch bundles two related changes, support for --test on
relation-get, unit-get and config-get.
This should be similar to the additions made in the golang version.

Also this changes to always use a formatter for output and the smart
output formatter was changed to
YAML dump collection types, normal string values are still printed w/o
serialization.

https://code.launchpad.net/~bcsaller/juju/sane_output_test_option/+merge/106067

(do not edit description out of merge proposal)

Please review this at https://codereview.appspot.com/6216053/

Affected files:
   A [revision details]
   M juju/hooks/cli.py
   M juju/hooks/commands.py
   M juju/hooks/tests/test_invoker.py