Include cleanup: Selection.hpp

It does not need 3DScene.hpp and Model.hpp
And it does not to be included by GLGizmoBase.hpp

src/slic3r/GUI/Gizmos/GLGizmoBase.cpp

@@ -4,14 +4,9 @@
 #include <GL/glew.h>
 
 #include "slic3r/GUI/GUI_App.hpp"
-#include "slic3r/GUI/GLCanvas3D.hpp"
-
-
 
 // TODO: Display tooltips quicker on Linux
 
-
-
 namespace Slic3r {
 namespace GUI {