Creates a Polygon
        @type  points: string in the form "x1,y1 x2,y2 x3,y3"
        @param points:  all points relevant to the polygon
        @type  strokewidth: string or int
        @param strokewidth:  width of the pen used to draw
        @type  stroke: string (either css constants like "black" or numerical values like "#FFFFFF")
        @param stroke:  color with which to draw the outer limits
        @type  fill: string (either css constants like "black" or numerical values like "#FFFFFF")
        @param fill:  color with which to fill the element (default: no filling)
        @return:  a polygon object

def createPolygon(self, points, strokewidth=1, stroke='black', fill='none'):
        """
        Creates a Polygon
        @type  points: string in the form "x1,y1 x2,y2 x3,y3"
        @param points:  all points relevant to the polygon
        @type  strokewidth: string or int
        @param strokewidth:  width of the pen used to draw
        @type  stroke: string (either css constants like "black" or numerical values like "#FFFFFF")
        @param stroke:  color with which to draw the outer limits
        @type  fill: string (either css constants like "black" or numerical values like "#FFFFFF")
        @param fill:  color with which to fill the element (default: no filling)
        @return:  a polygon object
        """
        style_dict = {'fill':fill, 'stroke-width':strokewidth, 'stroke':stroke}
        myStyle = StyleBuilder(style_dict)
        p = Polygon(points=points)
        p.set_style(myStyle.getStyle())
        return p