Prevent future uses of print statements where logging should be used instead

[khatchad]

Per #331, we want to refactor the print statements to instead use logging. But, some print statements are OK, like the ones used in the CLI. Once #331 is fixed, we would like to prevent future uses of print statements where logging should be preferred, perhaps by failing the build if print statements instead of logging are used in inappropriate places. Note again that print statements in the CLI code are perfectly appropriate.