The two films screened in curator Margarita de la Vega-Hurtado’s CINEMATHEQUE: Latin American “Third Cinema” program at Rice University’s Media Center are classic examples of agitprop filmmaking at its best and/or most blatant. Shot between 1966 and 1972, Chircales (Brickmakers), by noted Colombian filmmaker Marta Rodriguez, is a not-too-subtle indictment…