Reverted change to the AreaCurve() method that allowed adjacent vertices to be too close together.  This wasn't the problem and it introduced a fault in the conversion
Changed the ContiguousPath::Plane() method so that the default XY plane used for linear elements is translated to the start point of the element.  This allows the distance between the linear element and another plane to be compared in a more meaningful way (as is done in the ::Intersect() method)