Draws lines between points in a given list
[(x1,y1),...,(xn,yn)] to form a shape.
draw_polygon(points_list,fill_in = True):
points_list: A list
[x1,y1,x2,y2,....xn,yn] with at least 3 points
fill_in: Boolean that selects if the polygon will be filled in (white). Default to True.