Create geoscript.index module for spatial index support #69
Description
Geoscript Groovy has a geoscript.index package for spatial index support.
https://github.com/geoscript/geoscript-groovy/tree/master/src/main/groovy/geoscript/index
https://jericks.github.io/geoscript-groovy-cookbook/#spatial-index-recipes
Initially, we should support JTS's QuadTree, and STRtree spatial index classes.