First part of Chapter 3: Voronoi cells and exact SVP/CVP

Signed-off-by: Nicolai Hähnle <nhaehnle@gmail.com>
Figure for Voronoi cell scaling

Signed-off-by: Nicolai Hähnle <nhaehnle@gmail.com>
Some cleanups in chapter 3 (Voronoi cells)

Signed-off-by: Nicolai Hähnle <haehnle@or.uni-bonn.de>