ENH: DependencyGraph: Set the parent even in the case when a vertex

has already been discovered. In the case of a cycle, this allows for
correct paths for diagnosing the problem. Example:

        -> 3
      /
1 -> 2  -> 4
      \    /
        <-

Previously, findPathDFS(...) which uses this->Parent[to] found for 4 to 2:
(4,1,2). Now it finds (4,2) because the new parent for 2 is 4.

Libs/Core/ctkDependencyGraph.cpp

@@ -138,9 +138,9 @@ void ctkDependencyGraph::ctkInternal::traverseUsingDFS(int v)
 		y = this->edge(v, i);
 		if (this->P->shouldExcludeEdge(this->edge(v, i)) == false)
 		  {
+      this->Parent[y] = v;
 			if (this->Discovered[y] == false)
 			  {
-				this->Parent[y] = v;
 				this->traverseUsingDFS(y);
 			  } 
 			else