This is the chamber music equivalent of the “Eroica” Symphony and was Beethoven’s dramatic breakthrough in quartet composition. The program began with four works by Gen Z composers, thus delineating a spectrum of works by composers born between 1913 and 2005. One of Ligeti’s responses was his 1951 “Concert Românesc” (“Romanian Concerto”), which reflected his genuine interest in folk music. Capping the program and the entire festival was Salonen’s Cello Concerto of 2016, originally written for Yo-Yo Ma and the Chicago Symphony. Its performance ended this year’s festival literally on the cello’s high note, a B-flat way up in the seventh octave.