Add tsv and txt extensions for CSV.
Add tsv and txt extensions for CSV.

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