Director Timothy Nelson has created a new performing edition of Henry Purcell’s The Fairy Queen for Iford, which picks out the most familiar scenes and divides them into four “Nights” (the Mechanicals’ rehearsal, Oberon and Titania’s quarrel, the human lovers’ confusion, and the Mechanicals’ play), framed by a Prologue and Epilogue. Purcell’s music is not only exquisite, but here is…