Jerome Lawrence, the late, great author of “Inherit the Wind,” had several commandments for playwrights. High on the list was “Thou shalt not take the money of thine audience without letting them know what goeth on.” I’d say, observationally, that a fair portion of the audience at the opening night of Mia Chung’s “Catch As Catch Can” at Steppenwolf Theatre found themselves scratching their heads over precisely who was who and when and, yet more importantly, to what end in the here and now.