support for .NET framework 3.5

Still have bugs

Net35/HandyControl_Net35/Shell/Standard/IObjectWithProgId.cs

@@ -0,0 +1,14 @@
+namespace Standard
+{
+    using System;
+    using System.Runtime.InteropServices;
+
+    [ComImport, Guid("71e806fb-8dee-46fc-bf8c-7748a8a1ae13"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    internal interface IObjectWithProgId
+    {
+        void SetProgID([MarshalAs(UnmanagedType.LPWStr)] string pszProgID);
+        [return: MarshalAs(UnmanagedType.LPWStr)]
+        string GetProgID();
+    }
+}
+