flexible roundbox lib for polyhedron

* English
(German version below.)

If someone want to construct a cuboid with rounded corners and edges, most people use the following construct:

minkowski()
{
cube([20,40,10], center=true);
scale([4,11,5])
sphere(r=1,$fn=32);
}

If you want just a rounded cuboid, this creates the desired result, but only that. If you want any further modification, you are restricted to what openSCAD gives you, i.e. `difference()`, `multmatrix()`, e.t.c..
Oth