Rename PdfViewerWindow to DocumentViewerWindow

WGneu/Documents/Pdf.cs

@@ -48,7 +48,7 @@ namespace WGneu.Documents {
         }
 
         public static void Display(string title, string path) {
-            var w = new PdfViewerWindow(title, path);
+            var w = new DocumentViewerWindow(title, path);
             w.Show();
         }
     }