Use of proprietary fonts could be avoided

[rjpereira]

The setup of hsl-map-style use a fontstack.zip file that is encrypted (probably due to use of Gotham font from adobe).
Although I could understand custom deployments to want to style their maps ina particular way, this distribution requires always some changes to have it working.
I got it working with Open Sans pbf that I got from https://github.com/lukasmartinelli/glfonts .
Would suggest that book could be changed for Open Sans Regular and Gotham Book by Gotham Light.. Works nicely.