[Missing] test/2018/spline.dwg Missing control point information

[FishOrBear]

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10 | Control points (in WCS); one entry per control pointDXF: X value; APP: 3D point

[rurban]

As annotated in dwg.spec: FIXME: calculate knots and ctrl_pts from fit_pts for DXF. The algorithm is described in https://github.com/mozman/ezdxf/blob/master/src/ezdxf/math/bspline.py (MIT), to be put into geom.c