(Credit: Kristen Loken / San Francisco Opera) San Francisco Opera ended its Fall Season by going back to basics with Donizetti’s “L’Elisir d’Amore,” boy loves girl, girl not at all sure about boy, charlatan quack-doctor with his “magical elixir” will cure that, comic hi-jinx, chorus of happy men and women, hotel by the sea, hot air balloon, motorized vespas, and {…}