fix mapbox data browsing in the case of no proxy - closes #1594
fix mapbox data browsing in the case of no proxy - closes #1594

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