Polygons added as layers are always filled on iOS

[the-unforgiven]

Hi,
I noticed that polygons added as layers are always filled on iOS - the bool fill parameter is ignored in DrawPolygon(), see OsmSharp.iOS.UI.CGContextRenderer.

I replaced

                target.Target.CGContext.FillPath ();

with

if (fill) {
                target.Target.CGContext.FillPath ();
            } else {
                target.Target.CGContext.DrawPath (CGPathDrawingMode.Stroke); }