The Boston Symphony Orchestra will conclude its season-long centennial celebration of Leonard Bernstein on Aug. 25, the Lawrence native’s 100th birthday, with a gala concert at Tanglewood, where the legendary composer and conductor’s influence continues to be felt to this day.A protégé of Tanglewood founder Serge Koussevitzky, the BSO's music director from 1924 to 1949, Bernstein was active at Tanglewood from his 1940 arrival until his final concerts conducting [...]