As courtroom dramas go, “Denial” is tasteful, to a fault. In playwright David Hare’s screenplay, based on actual events, you won’t hear anyone shouting something like “You can’t handle the truth!” from the stand. No one will ever accuse director Mick Jackson (“L.A. Story”) of taking sensational liberties with the truth. Then again, where is the excitement? Jackson capably directs this subdued interpretation of Deborah Lipstadt’s 2005 memoir “History on Trial: My Day in Court With a Holocaust Denier.” The film begins in 1996 when British writer David Irving sued Lipstadt, a historian at Emory University, and her publisher for libel, after she referred to him in writing as a Holocaust denier.