This year’s Festival of Contemporary Music at Tanglewood (in Lenox, Massachusetts) was curated by three youngish stars of the new music community: pianist Jacob Greenberg (ICE), cellist Kathryn Bates (Del Sol Quartet), and violist Nadia Sirota (Q2, ACME).  Each planned  a chamber music concert, consisting of commissioned new works and contemporary repertory selections. The curators combined forces with the BSO in selecting pieces for the festival’s finale, an orchestra concert conducted by Stefan Asbury and Vinay Parameswaran.   Commissioned works included vocal pieces by Nathan Davis and Anthony Cheung, a string quartet (with copious use of water-filled glasses and glass