Fixed skylight in empty ChunkSnapshot sections to be 15 instead of 0.
Fixed skylight in empty ChunkSnapshot sections to be 15 instead of 0.

Also, fixed logic for isSectionEmpty.

Tonodus/WaterGleam,Tonodus/GlowSponge,kukrimate/Glowstone,GlowstoneMC/GlowstonePlusPlus,Tonodus/WaterGleam,LukBukkit/GlowstonePlusPlus,GlowstonePlusPlus/GlowstonePlusPlus,Postremus/GlowstonePlusPlus,LukBukkit/GlowstonePlusPlus,GreenBeard/GlowstonePlusPlus,Tonodus/GlowSponge,LukBukkit/GlowstonePlusPlus,jimmikaelkael/GlowstonePlusPlus,GlowstoneMC/GlowstonePlusPlus,GlowstonePlusPlus/GlowstonePlusPlus,GlowstonePlusPlus/GlowstonePlusPlus,GlowstoneMC/GlowstonePlusPlus,LukBukkit/GlowstonePlusPlus,BlazePowered/Blaze-Server,jimmikaelkael/GlowstonePlusPlus,kukrimate/Glowstone,keke142/GlowstonePlusPlus,kukrimate/Glowstone,GlowstonePlusPlus/GlowstonePlusPlus,BlazePowered/Blaze-Server,BlazePowered/Blaze-Server,Tonodus/WaterGleam,Tonodus/GlowSponge,Postremus/GlowstonePlusPlus,GlowstoneMC/GlowstonePlusPlus,BlazePowered/Blaze-Server,Postremus/GlowstonePlusPlus,Postremus/GlowstonePlusPlus,GreenBeard/GlowstonePlusPlus,jimmikaelkael/GlowstonePlusPlus,kukrimate/Glowstone,jimmikaelkael/GlowstonePlusPlus,GreenBeard/GlowstonePlusPlus,Tonodus/WaterGleam,keke142/GlowstonePlusPlus,keke142/GlowstonePlusPlus,keke142/GlowstonePlusPlus,GreenBeard/GlowstonePlusPlus,Tonodus/GlowSponge