A genuine masterpiece inspires musicians to adopt, adapt, or transcribe it without losing any of its greatness. Period-instrument ensemble Nevermind (Anna Besson, flute; Louis Creac’h, violin; Robin Pharo, viola da gamba; and Jean Rondeau, harpsichord and organ) has taken a creative look at Bach’s famous Goldberg Variations and made their own stylishly insightful “variations” on the work. As they themselves …