A hole drilled square to a flange's panel, not only the base's, is now a flat cut-out of the sheet: it unfolds with its panel to where the bend allowance puts it, shows in the flat pattern and DXF as a circle, and survives unfold and refold. A pocket tool spans the cut-outs already inside it (a counterbore's hole), so the order they are made in no longer matters. Fixes #560.