“This could be my last opera,” predicted Philippe Boesmans in February of last year, just two months before his death at 85. “I’ve done tragedies…so I decided that I have to finish with total lightness, total insouciance.” Virtually unknown in the U.S., the Belgian composer garnered European success with exquisite settings of serious drama: Schnitzler’s “Reigen“ (1993), Shakespeare’s “Winter’s Tale” {…}