PLConsol() is a function which takes a geom, which must be a polylist,
as its argument and returns a version of the polylist which has
no repeated vertices. Two vertices are considered to be identical if
they are within prec of one another. The comparison takes into
account only the location of the points, not their normals or colors.
The vertices of the resultant polyline have been sorted, and so there
order bears no resemblance to the order of the point in the original