Update total tiles when changing bounds. Fixes #1148.
Update total tiles when changing bounds. Fixes #1148.

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