Create a GeoJSON file for all named places

[waldoj]

We should have a single GeoJSON file that includes every named, GNIS-bearing feature referred to in all of the collected data. User agents can use that to determine the boundaries of the listed features.

(Separately, we'll include GeoJSON within each species file, etc. that describes the totality of the bounded area(s), per #1.)

This emerged from an exchange with @feomike on ca6d373.

[waldoj]

Note that @davidmurr is working on this.