SVGRenderingHelper: Add Bezier curve drawing
SVGRenderingHelper: Add Bezier curve drawing

This commit adds the capability of drawing cubic Bezier curves to the
SVGRenderingHelper class. For doing so, it utilizes a public static
helper function that approximates Bezier curves into polygons; those
approximations are then drawn with the custom drawPolyline method.

JangoBrick/php-svg