support for .NET framework 3.5

Still have bugs

Net35/HandyControl_Net35/Shell/Standard/FOF.cs

@@ -0,0 +1,25 @@
+namespace Standard
+{
+    using System;
+
+    internal enum FOF : ushort
+    {
+        ALLOWUNDO = 0x40,
+        CONFIRMMOUSE = 2,
+        FILESONLY = 0x80,
+        MULTIDESTFILES = 1,
+        NO_CONNECTED_ELEMENTS = 0x2000,
+        NOCONFIRMATION = 0x10,
+        NOCONFIRMMKDIR = 0x200,
+        NOCOPYSECURITYATTRIBS = 0x800,
+        NOERRORUI = 0x400,
+        NORECURSEREPARSE = 0x8000,
+        NORECURSION = 0x1000,
+        RENAMEONCOLLISION = 8,
+        SILENT = 4,
+        SIMPLEPROGRESS = 0x100,
+        WANTMAPPINGHANDLE = 0x20,
+        WANTNUKEWARNING = 0x4000
+    }
+}
+