[7] It’s 18th century France and everyone’s the Vavavoom de Floofenberg dressed to the nines and powdered like a doughnut. Yes, Dangerous Liaisons is one of those dreaded costume dramas. But like any good one, if you strip away the gilding and highfalutin language, it’s really a tale as old as time — modern, even. Glenn Close is a horny, devious widow who employs her …