color and PMTiles utils

[crazycapivara]

and first version of maplibre express

closes #95

[cboettig]

@crazycapivara We're enjoying using this from the branch but would love to see this on pypi. Really appreciate the fantastic work in this cool package.

[crazycapivara]

@cboettig Yep. You are right. Need to merge. I will do it in the next few days :-)

[cboettig]

🎉 🎉 Thank you very much, this is fantastic!