Show filled form fields by default

[Jonowa]

If you set in file PdfDocument.cs in line 308 the last parameter to "true", filled form fields will be shown by default:
return Render(page, width, height, dpiX, dpiY, rotate, flags, true);
I've compiled it on my own machine and tested it successfully.

[m1l]

This was not enough on my pdf files and I had to do
var image = pdfDoc.Render(page, width, height, 96, 96, PdfRenderFlags.ForPrinting | PdfRenderFlags.Annotations);