update to latest carto@0.9.6 and millstone@0.6.12
update to latest carto@0.9.6 and millstone@0.6.12

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