Suppress Week 16 in longitudinal results if season has 15 weeks

[cooperjaXC]

In the event of weird Labor Day fallings, some CFB seasons will have 16 weeks and an extra bye for every team. So the shell of longitudinal results in v2.0 has room for 16 weeks + Final. If week 15 and Final are both filled out, drop week 16 from printed results, and ensure it doesn't show up in the longitudinal graphs (a la #19).