bounding box computation is now const correct

common/BaseObjectData.cc

@@ -284,7 +284,7 @@ void BaseObjectData::manipPlaced( bool _placed ) {
   manipPlaced_ = _placed;
 }
 
-void BaseObjectData::getBoundingBox(ACG::Vec3d& bbmin, ACG::Vec3d& bbmax){
+void BaseObjectData::getBoundingBox(ACG::Vec3d& bbmin, ACG::Vec3d& bbmax) const {
 
   // Single pass action, as the bounding box is not influenced by multipass traversal
   ACG::SceneGraph::BoundingBoxAction act;

common/BaseObjectData.hh

@@ -207,7 +207,7 @@ class DLLEXPORT BaseObjectData : public BaseObject
     void manipPlaced( bool _placed );
 
     /// get the bounding box of the object
-    void getBoundingBox(ACG::Vec3d& bbmin, ACG::Vec3d& bbmax);
+    void getBoundingBox(ACG::Vec3d& bbmin, ACG::Vec3d& bbmax) const;
     
     /** \brief Set the draw mode for the object
      * @param _mode  The draw mode that should be active for this object