Today is the birthday of one-hit wonder Jean-Joseph Mouret (1682-1738). If you’re old enough to remember this as the theme to “Masterpiece Theatre,” we can be friends. Now, of course, the series is simply called “Masterpiece,” just as Dunkin’ Donuts is now Dunkin’. The national attention span, apparently, has withered to the point that we can’t even be relied upon to absorb a full name.