CRSEPS ( bc, path, bs, ifail )
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  Sweep a B-curve into a B-surface

Receives:
  KI_tag_b_curve           *bc             --- B-curve to sweep
  KI_vec_displacement       path           --- translation vector

Returns:
  KI_tag_b_surface         *bs             --- result of sweep
  KI_cod_error             *ifail          --- failure code


Description:
  The B-curve is moved along the path vector sweeping out a B-surface.

  Returned surface 'bs':
  . The curve lies along the v = 0 parameter line of the surface.
  . The surface has the same dimension as the curve.
  . The u order of the surface is the order of the curve.
  . The v order of the surface is 2.
  . The surface normal is in the direction of the cross product of the curve
    tangent and the path vector.

  In general this procedure may construct a self-intersecting surface.