Earlier this month, in a rare moment of media detente, Boston's finest film critics climbed onstage at the Brattle and talked b-movies, to promote DaCapo's new The B-List: The National Society of Film Critics on Low Budget Beauties, Genre-Bending Mavericks, and Cult Classics We Love. Amazingly, even though Jay Carr was on the panel, the Globe's Ty Burr, the Herald's James Verniere, and the Phoenix's own Peter Keough were able to get a few words edgewise.