bump node-mapnik version to 0.5.13
bump node-mapnik version to 0.5.13

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