SEASON PREMIERE: Part 1 of 2. For the first shows back without the late Cory Monteith, Glee is providing a substantial distraction: a two-part episode built around the music of the Beatles. American Idol usually tanks when it takes on the Lennon-McCartney catalog, but Glee, when Chris Colfer’s Kurt sang a slow, soulful “I Want to Hold Your Hand” a while back, did it beautifully. So there’s hope. And there’s nothing they can sing that can’t be sung. It’s easy…