The American Repertory Theater’s opening night performance of Eve Ensler’s “In the Body of the World,’’ directed by ART artistic director Diane Paulus, met with a rousing ovation from the audience. The show was followed by a discussion with social activist-author Naomi Klein and Monique Wilson, director of One Billion Rising, the movement founded by Ensler to end rape and sexual violence against women. Also there was civil rights advocate Kimberlé Crenshaw.