support for .NET framework 3.5

Still have bugs

Net35/HandyControl_Net35/Shell/Standard/GPS.cs

@@ -0,0 +1,19 @@
+namespace Standard
+{
+    using System;
+
+    internal enum GPS
+    {
+        BESTEFFORT = 0x40,
+        DEFAULT = 0,
+        DELAYCREATION = 0x20,
+        FASTPROPERTIESONLY = 8,
+        HANDLERPROPERTIESONLY = 1,
+        MASK_VALID = 0xff,
+        NO_OPLOCK = 0x80,
+        OPENSLOWITEM = 0x10,
+        READWRITE = 2,
+        TEMPORARY = 4
+    }
+}
+