Mark golden league songs as gold exclusive

Merge pull request noahm#18 from ranatalus/master

Minor correction in extreme.json

Sort game selector by release

Clean up & document new forced distribution logic

Correct jacket for supernova la bamba

Merge pull request noahm#11 from FuriousDCSL/master

Added KAC songs

Merge pull request noahm#10 from FuriousDCSL/master

New songs 11/14

Image optimization pass

Move credits to alert box, add update banner