Oscar winner Morgan Freeman will be in town Sunday to receive an honorary degree at BU’s commencement. The 75-year-old actor, who won an Academy Award for his role in “Million Dollar Baby,’’ said in a statement that he’s proud to receive a Doctor of Humane Letters degree. “However,’’ he added, “we must never lose sight that there is no such thing as an honorary education.’’ Teach for America founder Wendy Kopp will deliver the commencement address and Robert Langer, the MIT professor and inventor, will also receive an honorary degree. . . . Meanwhile, singer Graham Nash — one-third of Crosby, Stills & Nash — and Pulitzer Prize-winning historian David McCullough will address Lesley University’s grads Saturday.