sheet.flat_pattern reports every cut-out exactly in a new cutout_shapes list, parallel to cutouts: a round hole as a circle, other cut-outs as their lines, arcs and (for other curves) polylines. Pockets get the same. The DXF writer and the JSON share one circle test. Un-ignores the #542 regression test. Fixes #542. Co-authored-by: jonaswre <[email protected]>