Import lwIP contrib rep

... from http://git.savannah.gnu.org/cgit/lwip/lwip-contrib.git/ into contrib/ subdir, STABLE-2_1_0_RELEASE tag
lwIP contrib is now officially frozen
TODO: Fix build

contrib/apps/LwipMibCompiler/SharpSnmpLib/Mib/Elements/Entities/NotificationGroup.cs

@@ -0,0 +1,22 @@
+/*
+ * Created by SharpDevelop.
+ * User: lextm
+ * Date: 2008/5/21
+ * Time: 19:34
+ * 
+ * To change this template use Tools | Options | Coding | Edit Standard Headers.
+ */
+
+namespace Lextm.SharpSnmpLib.Mib.Elements.Entities
+{
+    /// <summary>
+    /// Description of NotificationGroupNode.
+    /// </summary>
+    public sealed class NotificationGroup : EntityBase
+    {
+        public NotificationGroup(IModule module, SymbolList preAssignSymbols, ISymbolEnumerator symbols)
+            : base(module, preAssignSymbols, symbols)
+        {
+        }
+   }
+}