Hordes of eager college students converge upon the small lobby of the Amherst Cinema, wide-eyed and chatting loudly as they quickly form into lines leading up to the ticket counter. Some are already singing the nostalgic tune and excitedly dancing in the packed lobby. It’s going to be a full house tonight for the premiere of “Space Jam”, a part of the new “Late Nites @ Amherst Cinema” cult classics series. At last week’s showing of “The Room” and at this week’s showing of R.