Make ChppPlanner::roadmapBuilderIthProblem() virtual.

This enables ChppWalkPlanner to insert a delegate in order to customize roadmap
builder behavior.

ChangeLog

+	45. Make ChppPlanner::roadmapBuilderIthProblem() virtual.
 	44. In ChppPlanner::solveOneProblem, test direct path with all validators of device.
 	43. Added some tests in ChppPlanner::solveOneProblem() for robustness purposes.
 	42. In ChppPlanner::solveOneProblem, if path is null after calling rdmBuilder return KD_ERROR.

include/hppCore/hppPlanner.h

@@ -175,8 +175,8 @@ class ChppPlanner {
      \xrefitem <send-notif> "Notification" "Send Notification" Send ID_HPP_ADD_ROADMAP.
      \xrefitem <send-notif> "Notification" "Send Notification" Send ID_HPP_REMOVE_ROADMAP.
   */
-  ktStatus roadmapBuilderIthProblem(unsigned int rank, CkwsRoadmapBuilderShPtr inRoadmapBuilder,
-				    bool inDisplay=false);
+  virtual ktStatus roadmapBuilderIthProblem(unsigned int rank, CkwsRoadmapBuilderShPtr inRoadmapBuilder,
+					    bool inDisplay=false);
 
   /** 
     \brief Get roadmap builder of i-th problem.