`Particle::do_motor_behaviours` doesn't recognize all the cases of the face change possibility

[kolayne]

Not only the map_node neighbours but also their neighbours should be checked in this piece of code:

minds_crawl/src/simulation_objects/Particle.cu

Lines 41 to 51 in f4dc1c9

	MapNode *node_neighbors[] = {map_node->get_left(), map_node->get_top(), map_node->get_right(),
	map_node->get_bottom()};
	for(MapNode *neighbor : node_neighbors)
	{
	if(neighbor->get_face() != map_node->get_face()) // If any of the neighbor nodes is on a different face
	{
	// Then particle might move to a different face, so project coordinates to the polyhedron's surface
	end = get_projected_vector_end(coordinates, end, map_node->get_face(), map_node->get_polyhedron());
	break;
	}
	}

I would really appreciate a comment from @tanya-kta with a pretty detailed explanation of the reason for this (probably with a picture)