other note: working with different voxel-classes might not work because clone, while templated will probably always be used as Voxel-clone since the voxel is defined as Voxel* (correct?). When multiple voxel-classes are introduced by the new loader (#76), a kind-of-double-dispatch will be used as shown in the comment, where voxel->addtocluster() will call cluster->addVoxel(this), and this will be propery-typed, effectively (hopefully) calling the correct overload