Racism, sexism, economic disparity, and stagnation roil beneath the surface Caroline Thibodeaux's (an embattled yet resilient Sharon B Clarke) deep unhappiness, disappointment, and resistance to change in Tony Kushner's "Caroline, or Change." Currently enjoying a successful revival at Roundabout's Studio 54, the Kushner/Tesori musical focuses on Caroline's long days in the Louisiana "under water" basement of the Gell…