Implement `func intersects(_ other: Geometry) -> Bool`

[tonystone]

A comprehensive test suite needs to be developed for all variations of geometries for the intersects function.

[tonystone]

Add to protocol Geometry and all implementing types with the syntax:

    ///
    /// - Returns: true if this geometric object “spatially intersects” the other Geometry.
    ///
    func intersects(_ other: Geometry) -> Bool