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["T.vanLankveld" <>]

As an additional note, I did some tests on my data and found something I
thought was weird, but this may seem like a beginners mistake to the more
veteran CGAL-programmers:

I did the following tests on each triangle in the Delaunay triangulation
before using the points to construct the alpha-shape:

- triangle.is_degenerate()
- CGAL::collinear(p0, p1, p2)
- Rational rdx1 = Rational(p1.x())-Rational(p0.x()), rdy1 =
Rational(p1.y())-Rational(p0.y());
  Rational rdx2 = Rational(p2.x())-Rational(p0.x()), rdy2 =
Rational(p2.y())-Rational(p0.y());
  rdx2*rdy1 == rdx1*rdy2
- NumberType dx1 = p1.x()-p0.x(), dy1 = p1.y()-p0.y();
  NumberType dx2 = p2.x()-p0.x(), dy2 = p2.y()-p0.y();
  CGAL::compare(dx2*dy1, dx1*dy2) == CGAL::EQUAL
- dx2*dy1 == dx1*dy2

Only the last two checks returned true when using a
Filtered_kernel<Cartesian<double>>.
Rational here is Quotient<MP_Float> and NumberType is double.

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