Fix of previous commit: plasticity_state should be in both cases
Initial implementation of quadratic shape matching

It works! :muscle: But graphical vertices are not updated properly yet (still only linear)
Update cluster indices and count for physical vertices too

Allows to do paint_model on  low_model as well as on high_model
Implemented visualization of normals of graphical model

Also added a flag in main.cpp to disable update on GPU (otherwise normals won't be updated)
This required adding a new feature of AbstractModel: add_subscriber and notify_subscriber

Also fixed squeeze_sphere: now it updates normals properly
Updating graphical vertex positions (but not vectors) quadratically
Vertex struct change! Make normal 3-vector (it is already used in shader as 3-vector)

Updated VERTEX_DECL_ARRAY and VERTEX_INFO accordingly
First implementation of generate_normals: currently very slow