Written by DCist contributor Valerie Paschall Fitting the Montreal six-piece The Besnard Lakes into the small Backstage at the Black Cat seemed like a stretch. Containing the dense sound of three guitars and keyboards in the small room without destroying onlookers’ eardrums looked like it would take a small feat of science. Yet, the true feat was that even in that small room for no more than 75 people, The Besnard Lakes effectively conveyed…