feat: particle aging

particle-track-and-trace/src/layers/LGlyphLayer.h

@@ -13,7 +13,9 @@
 class LGlyphLayer : public Layer {
 private:
   vtkSmartPointer<vtkPoints> points;
+  vtkSmartPointer<vtkPolyData> data;
   vtkSmartPointer<vtkIntArray> particlesBeached;
+  vtkSmartPointer<vtkIntArray> particlesAge;
   std::unique_ptr<AdvectionKernel> advector;
   std::shared_ptr<UVGrid> uvGrid;
   int dt = 3600;