add more code comments to osx packaging doc
add more code comments to osx packaging doc

Zhao-Qi/tilemill,isaacs/tilemill,fxtentacle/tilemill,tizzybec/tilemill,nyimbi/tilemill,nyimbi/tilemill,paulovieira/tilemill-clima,Teino1978-Corp/Teino1978-Corp-tilemill,tilemill-project/tilemill,paulovieira/tilemill-clima,fxtentacle/tilemill,mbrukman/tilemill,tizzybec/tilemill,fxtentacle/tilemill,tizzybec/tilemill,Teino1978-Corp/Teino1978-Corp-tilemill,fxtentacle/tilemill,isaacs/tilemill,tilemill-project/tilemill,tizzybec/tilemill,Zhao-Qi/tilemill,Teino1978-Corp/Teino1978-Corp-tilemill,nyimbi/tilemill,MappingKat/tilemill,nyimbi/tilemill,florianf/tileoven,florianf/tileoven,mbrukman/tilemill,nyimbi/tilemill,Zhao-Qi/tilemill,Zhao-Qi/tilemill,mbrukman/tilemill,paulovieira/tilemill-clima,fxtentacle/tilemill,MappingKat/tilemill,paulovieira/tilemill-clima,MappingKat/tilemill,Teino1978-Corp/Teino1978-Corp-tilemill,MappingKat/tilemill,MappingKat/tilemill,tilemill-project/tilemill,paulovieira/tilemill-clima,Zhao-Qi/tilemill,tizzybec/tilemill,mbrukman/tilemill,Teino1978-Corp/Teino1978-Corp-tilemill,florianf/tileoven,isaacs/tilemill,mbrukman/tilemill