Triangle segment 3d intersection not always correct

[August Johansson]

Here's an example of a triangle and a segment that do not intersect, but the function IntersectionConstruction::_intersection_triangle_segment_3d says they do.

const std::vector<Point> tri = {{Point(0.7251036236715264,0.793686491949706,0.6903757954609298),
Point(0.394382926819093,0.7830992237586059,0.197551369293384),
Point(0.7251036236715273,0.7936864919497059,0.6903757954609298) }};

const std::vector<Point> seg = {{Point(0.6778055854963545,0.7956397277791267,0.4785615047675733),
Point(0.7214471458007253,0.7943539927910607,0.7214471458007252) }};

const std::vector<Point> intersection
   = IntersectionConstruction::_intersection_triangle_segment_3d(tri[0], tri[1], tri[2],
                                   seg[0], seg[1]);