THE PAPERHEAD The Paperhead myspace.com/lookingglasssound When Ryan Jennings, one of three Nashville teens behind the Paperhead, sings “Back to Those Days,” it’s obvious just which days he’s talking about. The trio’s debut flashes unabashedly back to 1968, its swimmy, fuzzy guitars and amorphous song structures evoking such psych-rock classics as the Third Bardo’s “I’m Five Years Ahead of My Time.” Because Jennings and his cohorts...