ShortestPathFinder - Handle a network with both two-way and one-way edges

ShortestPathFinder can currently handle either one-way or two-way streets, but it doesn't handle a mixed network well. Setting Cost Type to "By Two Attributes" and setting the reverse cost to a large number for one-way streets works as a workaround, but it's not very elegant and not foolproof. It would be great if we could indicate that a street is one-way by setting the reverse cost to negative or null.