Added a missing period to the README.
Added a missing period to the README.

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