Include GeoFeatures2 after Release

[vknabel]

GeoFeatures2 has not been released yet. Once it has, we want to add it to the index.

Excerpt from #19:

GeoFeatures*: GeoFeatures1 is running in production on many applications but as GeoFeatues2 has not been released yet. I do plan on releasing a beta shortly (within a few weeks or so) that contains the core, wkt, GeoJSN, and visualization. We'll follow on with the algorithms such as union, intersection, etc.

#### Geometry libraries
> _Tags: geometry, shape, map, point, linestring, polygon, multipoint, multilinestring, multipolygon, geojson, wkt, intersection, union, within, contains_
* [GeoFeatures](https://github.com/tonystone/geofeatures2): A lightweight, high performance geometry library in Swift. Runs on ios, osx, and linux.