The Met hasn’t performed an opera written by a woman since Ethel Smyth’s “Der Wald” in 1903. (Read that sentence one more time, and think about it hard.) So it’s a major statement for the company to be adding Ms. Saariaho’s “L’Amour de Loin” to its history — though this is a slightly delicate matter, since she has long resisted being categorized (read: ghettoized) as a “female composer.”