[GRASS-dev] v.voronoi update

[Paul Kelly]

And another comment from Martin about the algorithm used in the current 
GRASS v.voronoi:

I started studying Fortune sweepline algorithm. As soon as I make any 
significant progress with the implementation, I will inform you. As a 
matter of fact, original version of v.voronoi/delaunay uses a Fortune 
algorithm from netlib, which is quite a crude implementation. I am going 
to create a new code from scratch. However, I will use the previous code 
as a guideline. Even though I am going to implement the same algorithm, 
new code should be much more efficient, after I do some polishing.