add vtk geant solid and scene

src/HEP/Geant/Scene.h

@@ -58,6 +58,9 @@ public:
   
   ContainerBox* GetWorldBox() const;
 
+  /// Get the list of solids in the scene
+  const Vector<Solid*>& GetSolids() const;
+
   /// Set the primary generator (emitter) for the simulation.
   /// The Scene does NOT take ownership of the emitter.
   void SetEmitter(EmitterPrimary *emitter);