[doc] Add some comments in the development note.

doc/notes

@@ -6,11 +6,7 @@ In include/hpp/fcl/traversal:
     - bool initialize(MeshShapeCollisionTraversalNode<BV, S, NarrowPhaseSolver>& node, ...
     - bool initialize(ShapeMeshCollisionTraversalNode<S, BV, NarrowPhaseSolver>& node, ...
     - bool initialize(MeshCollisionTraversalNode<BV>& node,...
-    - bool initialize(MeshCollisionTraversalNodeOBB& node, ...
-    - bool initialize(MeshCollisionTraversalNodeRSS& node, ...
-    - bool initialize(MeshCollisionTraversalNodekIOS& node, ...
-    - bool initialize(MeshCollisionTraversalNodeOBBRSS& node, ...
-    
+
   - other do not.
 
     - bool initialize(MeshOcTreeCollisionTraversalNode<BV, NarrowPhaseSolver>& node, ...
@@ -23,3 +19,19 @@ In include/hpp/fcl/traversal:
     - bool initialize(ShapeMeshCollisionTraversalNodeRSS<S, NarrowPhaseSolver>& node, ...
     - bool initialize(ShapeMeshCollisionTraversalNodekIOS<S, NarrowPhaseSolver>& node, ...
     - bool initialize(ShapeMeshCollisionTraversalNodeOBBRSS<S, NarrowPhaseSolver>& node, ...
+    - bool initialize(MeshCollisionTraversalNodeOBB& node, ...
+    - bool initialize(MeshCollisionTraversalNodeRSS& node, ...
+    - bool initialize(MeshCollisionTraversalNodekIOS& node, ...
+    - bool initialize(MeshCollisionTraversalNodeOBBRSS& node, ...
+
+classes
+  - MeshCollisionTraversalNodeRSS,
+  - MeshCollisionTraversalNodekIOS,
+  - MeshCollisionTraversalNodeOBBRSS
+derive from
+  - MeshCollisionTraversalNode <RSS>,
+  - MeshCollisionTraversalNode <kIOS>,
+  - MeshCollisionTraversalNode <OBBRSS>.
+They store the relative position and orientation between two objects to test for
+collision. before calling overlap function, this additional information computes
+the relative positions of the bounding volumes.