Primitives: fixed Icosphere subdivision.

src/Primitives/Icosphere.h

@@ -64,6 +64,7 @@ template<std::size_t subdivisions> class Icosphere {
                 });
 
             MeshTools::clean(*indices(), *normals(0));
+            positions(0)->clear();
             positions(0)->reserve(normals(0)->size());
             for(auto i: *normals(0)) positions(0)->push_back(Point3D(i));
         }