Mapzen API key update

For those of you using Mapzen content inside Mantle, note that as of March they're requiring registration of a free API key in order to make tile requests as discussed on the Mapzen Blog.

All this requires you to do to continue using the Mapzen service within Mantle, is to go to their site and register for a free developer key. Mantle also has a button right next to the API key field that will take you directly to the Mapzen signup page.

Return to Mantle and simply copy and paste your Mapzen API key directly into the field in the Mantle Datasource.

Simple!