Add EPSV command

DearFTP/Connection/Commands/CommandsDispatcher.cs

@@ -12,6 +12,7 @@ namespace DearFTP.Connection.Commands
             new ClntCommand(),
             new CwdCommand(),
             new DeleteCommand(),
+            new ExtendedPassiveCommand(),
             new HelpCommand(),
             new FeaturesCommand(),
             new FileModificationTimeCommand(),

DearFTP/Connection/Commands/ExtendedPassiveCommand.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace DearFTP.Connection.Commands
+{
+    class ExtendedPassiveCommand : ICommand
+    {
+        public string[] Aliases { get; } = new string[]
+        {
+            "EPSV"
+        };
+
+        public void Execute(Session session, FtpStream stream, string alias, string argument)
+        {
+            session.DataConnection.Create();
+
+            int port = session.DataConnection.Port;
+
+            stream.Send(ResponseCode.ExtendedPassiveMode, $"Entering Extended Passive Mode (|||{port}|)");
+
+            session.DataConnection.AcceptClient();
+        }
+    }
+}

DearFTP/Connection/Commands/HelpCommand.cs

@@ -22,6 +22,7 @@
                     "CDUP",
                     "CWD",
                     "DELE",
+                    "EPSV",
                     "FEAT",
                     "HELP",
                     "LIST",