“Glee” airs touching tribute to Cory Monteith

The familiar voices of The New Directions sing  “Seasons of Love”  from the musical “Rent” to kick off “Glee’s” third episode, a touching, sob-your-eyes-out tribute episode to the late Cory Monteith. “Glee” decided to pay tribute to not only Cory, but also his character Finn the only way they knew how — through song. Key…