Add layers image
Add layers image

Add layers.png so if a non-retina display needs to load the legend at a
smaller scale the image shows up.

MaptimeMSP/nacis2015-map,dhmontgomery/nacis2015-map,WebDotNet/nacis2015-map,WebDotNet/nacis2015-map,neuhausr/nacis2015-map,aonilsson/nacis2015-map,neuhausr/nacis2015-map,MaptimeMSP/nacis2015-map,fawcett/nacis2015-map,aonilsson/nacis2015-map,kcantner/nacis2015-map,kcantner/nacis2015-map,fawcett/nacis2015-map,dhmontgomery/nacis2015-map