The major news from Boston was the ascendancy of Andris Nelsons, firming up his place as music director of the Boston Symphony Orchestra, which included a quickly agreed upon three-year extension of his contract into the 2020-2021 season. This announcement was soon followed by the less happy surprise for Bostonians of Nelsons also accepting an offer from the eminent Leipzig Gewandhaus, the orchestra whose music director was once no less than Felix Mendelssohn, to take on that very position, beginning in the 2017-2018 season, thus dividing the loyalties of the young maestro (who just turned 37), though evidently with the possibility of collaborations between the two orchestras. (Remember when some people were complaining about James Levine dividing his time between the BSO and the Metropolitan Opera?)