Ignore invalid catalog version on document load

Some invalid values in the optional Version field of the Catalog
caused an exception on PDFDocument construction.
It is now ignored and the document is created successfully.

Closes 65.

Autoported commit.
Original commit hash: [6bf4ecfb0]

Author: borislucas-dev

itext.tests/itext.kernel.tests/itext/kernel/pdf/PdfDocumentTest.cs

@@ -437,6 +437,13 @@ public virtual void RemovePageWithInvalidOutlineTest() {
                 ));
         }
 
+        [NUnit.Framework.Test]
+        public virtual void OpenDocumentWithInvalidCatalogVersionTest() {
+            PdfReader reader = new PdfReader(SOURCE_FOLDER + "sample-with-invalid-catalog-version.pdf");
+            PdfDocument pdfDocument = new PdfDocument(reader);
+            NUnit.Framework.Assert.IsNotNull(pdfDocument);
+        }
+
         private class IgnoreTagStructurePdfDocument : PdfDocument {
             internal IgnoreTagStructurePdfDocument(PdfReader reader)
                 : base(reader) {

itext.tests/itext.kernel.tests/resources/itext/kernel/pdf/PdfDocumentTest/sample-with-invalid-catalog-version.pdf

@@ -1971,9 +1971,13 @@ protected internal virtual void Open(PdfVersion newPdfVersion) {
                     if (catalog.GetPdfObject().ContainsKey(PdfName.Version)) {
                         // The version of the PDF specification to which the document conforms (for example, 1.4)
                         // if later than the version specified in the file's header
-                        PdfVersion catalogVersion = PdfVersion.FromPdfName(catalog.GetPdfObject().GetAsName(PdfName.Version));
-                        if (catalogVersion.CompareTo(pdfVersion) > 0) {
-                            pdfVersion = catalogVersion;
+                        try {
+                            PdfVersion catalogVersion = PdfVersion.FromPdfName(catalog.GetPdfObject().GetAsName(PdfName.Version));
+                            if (catalogVersion.CompareTo(pdfVersion) > 0) {
+                                pdfVersion = catalogVersion;
+                            }
+                        }
+                        catch (ArgumentException) {
                         }
                     }
                     PdfStream xmpMetadataStream = catalog.GetPdfObject().GetAsStream(PdfName.Metadata);

itext/itext.kernel/itext/kernel/pdf/PdfDocument.cs

@@ -1 +1 @@
-9c36eb28befb33da8e432e51468f2f845f484d1d
+6bf4ecfb0e4a409b1e5f2096045ca741e3fb854e