Issue #122: Added event OnLockTicksEvent (MT5)

MtApi5/Mt5LockTicksEventArgs.cs

@@ -0,0 +1,14 @@
+using System;
+
+namespace MtApi5
+{
+    public class Mt5LockTicksEventArgs : EventArgs
+    {
+        internal Mt5LockTicksEventArgs(string symbol)
+        {
+            Symbol = symbol;
+        }
+
+        public string Symbol { get; }
+    }
+}