I've made releases of a new 0.26.1 version of the 'neo4j-spatial' library for both Neo4j 3.4 and Neo4j 3.5. This version includes a new GeometryEncoder for the native point type introduced in Neo4j 3.4. This means you can now create nodes with point properties, instead of latitude:longitude, and index them with the library's in-graph RTree (or alternative geohash or hilbert curve indexes on lucene string indexes). See the details on the releases page: https://github.com/neo4j-contrib/spatial/releases
Keep in mind that it is probably more useful for you to index nodes with point properties using the built-in spatial index inside Neo4j itself. This new library feature is only for people that have other reasons for needing the library (like support for polygons), while at the same time want to use the new point type.