MAR DEL PLATA – Is Latin American cinema shifting mainstream? Art pics remain of course. Indeed, three standouts at Mar del Plata’s voluminous 22-title Work in Progress, which unspooled Thursday and Friday at the seaside resort – Daniel Rosenfeld’s “To the Center of the Earth,” Ana Pitarbarg’s “Alptraum” and Pablo Aguero’s “Madres de los Dioses,”...