Memory Improvement - Remove use of inputPoints and inputSegments in pyvoronoi.pyx

[fabanc]

Those variables duplicated this information duplicate the vector information that is already stored in the C++ class VoronoiDiagram in voronoi.hpp. This information is already contained in the private attributes points and segments

class VoronoiDiagram {
public:
	VoronoiDiagram();
	void AddPoint(Point p);
	void AddSegment(Segment s);
	void Construct();

       // ...

private:
	std::vector<Point> points;
	std::vector<Segment> segments;
	voronoi_diagram<double> vd;

};