Given a mesh and a set of edges, walk connected edges to form a set of paths. We do not distinguish betweens spans and loops if the input set of edges forms a loop, it will create an FEdgeSpan with those edges. If the input edges do not form loops, then paths will begin/end at vertices incident on 1 or >2 of the given edges (e.g. "dead ends" or "intersections" of paths.)
