Add test for tile rendering/serving.
Add test for tile rendering/serving.

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