Improve Shell Output When An Error Occurs

[matthewshirley]

This merge request improves the output for when an error occurs so that developers aren't overwhelmed by the

Example

Pact was unable to validate one or more interaction(s):

Interaction Mismatch #1
        Reason:
                Request was not matched (GET /alligators)

        Expected:
                - Expected query parameter 'nice' but was missing
                - Expected query parameter 'hungry' but was missing

Interaction Mismatch #2
        Reason:
                Request was unexpected

        Actual:
                GET /croc

Interaction Mismatch #3
        Reason:
                Request was missing

        Expected:
                GET /alligator