Add .gitignore.
Add .gitignore.

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