Cleanup & Fixes for .NET 5 (#309)

- [X] Fixes several bugs
- [X] Updates more ordinal issues
- [X] Cleans up the code a bit
- [X] Turns classes static that should have been
- [X] Changes TcpServer.Instances to a HashSet

Bumps release version

Projects/Server/Items/Container.cs

@@ -1847,7 +1847,7 @@ namespace Server.Items
                 {
                     line = line.Trim();
 
-                    if (line.Length == 0 || line.StartsWith("#"))
+                    if (line.Length == 0 || line.StartsWith("#", StringComparison.Ordinal))
                     {
                         continue;
                     }