PRESS PHOTO BY PAUL WILLISTEINDiane Wittry, second from left, conducted the Allentown Symphony Orchestra and The Eroica Trio: Erika Nickrenz, left, piano; Sara Sant'Ambrogio, second from right, cello, and Sara Parkins, right, violin, in Beethoven's “Triple Concerto” Nov. 4 and 5, Miller Symphony Hall, Allentown. After the Nov. 4 concert, members of the trio posed for photos and chatted with