Right when skeptics were really starting to dismiss disco and its simplistic, mechanical reputation, Nile Rodgers, Bernard Edwards, Tony Thompson, and their organization bum-rushed the Studio 54 doorman and dropped a musical masterclass. You know it for “Le Freak,” but the bell-rocking “I Want Your Love,”  jazz-inflected guitar showcase “Savoir Faire,” and heartbreak-as-liberation ballad “At Last I Am Free” proved there was far more than just a 12” worth of greatness.