Update IGraphXEdge.cs to support new ReversePath property
Update IGraphXEdge.cs to support new ReversePath property

Added support for reversing the geometry.  This is required for animating shapes along a path where the direction needs to be reversed without using the Storyboard.AutoReverse property.
slate56/GraphX,panthernet/GraphX,slate56/GraphX,edgardozoppi/GraphX,perturbare/GraphX,jorgensigvardsson/GraphX