Fix recognition of network paths in UrlUtil

DEVSIX-1668
DEVSIX-1670

Author: pavel-alay

itext/itext.io/itext/io/source/RandomAccessSourceFactory.cs

@@ -153,7 +153,10 @@ public IRandomAccessSource CreateSource(FileStream raf)
 		/// <exception cref="System.IO.IOException"/>
         public IRandomAccessSource CreateSource(Uri url) {
 #if !NETSTANDARD1_6
-            WebRequest wr = WebRequest.Create(Uri.UnescapeDataString(url.AbsoluteUri));
+			// Creation of web request via url.AbsoluteUri breaks UNC pathes (like \\computer-name\\img.jpg),
+			// url.LocalPath and url.AbsolutePath - break http links (like https://website.com/img.jpg).
+			// It seems enough to simply pass Uri instance as is, WebRequest seems to handle both escaping and UNC issues.
+            WebRequest wr = WebRequest.Create(url);
             wr.Credentials = CredentialCache.DefaultCredentials;
             Stream isp = wr.GetResponse().GetResponseStream();
 #else

itext/itext.io/itext/io/util/UrlUtil.cs

@@ -71,7 +71,11 @@ public static Uri ToURL(String filename) {
         public static Stream OpenStream(Uri url) {
             Stream isp;
             if (url.IsFile) {
-                isp = new FileStream(Uri.UnescapeDataString(url.AbsolutePath), FileMode.Open, FileAccess.Read);
+                // Use url.LocalPath because it's needed for handling UNC pathes (like used in local
+                // networks, e.g. \\computer\file.ext). It's safe to use #LocalPath because we 
+                // check #IsFile beforehand. On the other hand, the url.AbsolutePath provides escaped string and also breaks
+                // UNC path.
+                isp = new FileStream(url.LocalPath, FileMode.Open, FileAccess.Read);
             } else {
 #if !NETSTANDARD1_6
                 WebRequest req = WebRequest.Create(url);