Fix CircleCI badge to link to master branch
Fix CircleCI badge to link to master branch

GreenBeard/GlowstonePlusPlus,GlowstoneMC/GlowstonePlusPlus,GlowstoneMC/GlowstonePlusPlus,jimmikaelkael/GlowstonePlusPlus,GlowstoneMC/GlowstonePlusPlus,GlowstonePlusPlus/GlowstonePlusPlus,jimmikaelkael/GlowstonePlusPlus,LukBukkit/GlowstonePlusPlus,jimmikaelkael/GlowstonePlusPlus,GlowstonePlusPlus/GlowstonePlusPlus,jimmikaelkael/GlowstonePlusPlus,GreenBeard/GlowstonePlusPlus,LukBukkit/GlowstonePlusPlus,GreenBeard/GlowstonePlusPlus,GreenBeard/GlowstonePlusPlus,GlowstonePlusPlus/GlowstonePlusPlus,LukBukkit/GlowstonePlusPlus,GlowstonePlusPlus/GlowstonePlusPlus,LukBukkit/GlowstonePlusPlus,GlowstoneMC/GlowstonePlusPlus