Issue #82: Refactored MQL5 expert to use json in function OrderSend

MtApi5/MqlTradeRequest.cs

@@ -1,4 +1,5 @@
-using System;
+// ReSharper disable InconsistentNaming
+using System;
 
 namespace MtApi5
 {
@@ -22,6 +23,8 @@ namespace MtApi5
         public ulong Position { get; set; }                              // Position ticket
         public ulong PositionBy { get; set; }                            // The ticket of an opposite position
 
+        public int MtExpiration => Mt5TimeConverter.ConvertToMtTime(Expiration);
+
         public override string ToString()
         {
             return $"{Symbol}|{Volume}|{Price}|{Volume}|{Action}";