Threshold of 0.06 works best on planes when resolution is coarsened by 2x2 (320x240 organized cloud.)

I no longer look at plane-plane intersections. I check all pairs of planes, and compute cross product
to get the direction of the intersection. This probably generates the same results as computing
plane-plane intersections, WITHOUT finding a point on the plane.
Finding a point on a plane, can help identify whether the planes intersecting each other actually
do so within the cloud, or whether the intersection line is far from th planes. But for now, this is
ignored.