Move DummyIm out of BookletState tests and into test_utils module so we can reuse it for other state tests
Change ChoiceState to optionally accept case insensitive label-based answers in addition to number-based answers
Merge branch 'develop' into feature/issue-31-add-option-to-choicestate-to-allow-it-to-accept-a-choices-label-as-an-answer
Merge branch 'feature/issue-31-add-option-to-choicestate-to-allow-it-to-accept-a-choices-label-as-an-answer' into develop