Super Indie Karts: Early Access Update v0.63 - Super Summer Update

*Update v0.63* - June 22nd 2017 Summer's here and I'm super stoked to release this update, which adds support for more than 2 players in splitscreen. SplitscreenGP now supports 3 and 4 Players! SIK v0.63 changes: 3-4 pl…