Editor’s Note: “Flannery,” an American Masters segment on author Flannery O’Connor will air on PBS at 7 p.m. Tuesday, March 23. Larry Fink, a retired Hardin-Simmons University English professor, explains why O’Connor’s works are a “must read” for anyone who appreciates great literature. By LARRY E. FINK “I am no disbeliever in spiritual purpose and no vague believer. I see