Don't warn user about closing project when metaKey is held during click.
Don't warn user about closing project when metaKey is held during click.

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