The MMSO opens its season at the Piedmont Grand Opera House with the Macon debut of guest conductor Case Scaglione, former associate conductor of the New York Philharmonic. He is joined by two of today's most compelling soloists, violinist Stefan Jackiw and cellist Brannon Cho, for Brahms' Double Concerto for Violin and Cello. The program opens with David Diamond's jubilant Rounds and Prokofiev's witty Symphony No. 1, the “Classical.” Tickets are $25 to $35, and free for students of all…