Comment 4 for bug 1490324

The problem happen on arcs, usualy generated by ellipse tool, not happen on other shapes or paths -in a few test only-
I think also is a 2Geom related bug in the function "Geom::crossings" called from line 438 of meassure tool. I think so because measure tool detect, in this case, another crossing in the circle.

Also the problem aren't don't detect, in this case, two intersections, the problem are one of both is with bad position on the .ta value