Implemented Credential acquisition and release.

Program.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace NSspi
+{
+    public class Program
+    {
+        public static void Main( string[] args )
+        {
+            Credential cred = new Credential( SecurityPackage.Negotiate, CredentialType.Client );
+            cred.Dispose();
+
+        }
+    }
+}