Set flag so form field values are printed.

See http://partners.adobe.com/public/developer/en/pdf/PDFReference.pdf, Section 8.4.2 Annotation Flags

Author: Richard Bützer

plugins/acroform.js

@@ -1249,6 +1249,7 @@ window["CheckBox"] = AcroForm.CheckBox;
 AcroForm.TextField = function () {
     AcroForm.Field.call(this);
     this.DA = AcroForm.Appearance.createDefaultAppearanceStream();
+    this.F = 4;
     var _V;
     Object.defineProperty(this, 'V', {
         get: function () {