refs #2036: more robust activity processing
refs #2036: more robust activity processing

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