Support .NET Framework using Newtonsoft

LibIRD/PS3_DiscSFB.cs

@@ -2,7 +2,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Text;
-using System.Text.Json;
+using Newtonsoft.Json;
 
 namespace LibIRD
 {
@@ -68,7 +68,7 @@ namespace LibIRD
             // Read SFB file version
             byte[] buf = br.ReadBytes(2);
             Array.Reverse(buf);
-            Version = BitConverter.ToUInt16(buf);
+            Version = BitConverter.ToUInt16(buf, 0);
 
             // Process all field headers
             sfbStream.Seek(0x20, SeekOrigin.Begin);
@@ -131,11 +131,6 @@ namespace LibIRD
             }
         }
 
-        /// <summary>
-        /// Define JSON options once
-        /// </summary>
-        private readonly JsonSerializerOptions JsonOpts = new() { WriteIndented = true };
-
         /// <summary>
         /// Prints parameters extracted from PS3_DISC.SFB to a json object
         /// </summary>
@@ -143,7 +138,7 @@ namespace LibIRD
         public void PrintJson(string jsonPath = null)
         {
             // Serialise PS3_Disc.SFB data to a JSON object
-            string json = JsonSerializer.Serialize(Field, JsonOpts);
+            string json = JsonConvert.SerializeObject(Field, Formatting.Indented);
 
             // If no path given, output to console
             if (jsonPath == null)