added add_const/add_volatile/is_function

Fixed is_const/is_volatile to work with reference types
Fixed is_object to work with function types.
Fixed is_enum/is_empty to work with incomplete/abstract/function types


[SVN r9640]

libs/type_traits

@@ -1 +1 @@
-Subproject commit 04d2519bdd5094b991aa01d8b08a416c389fda74
+Subproject commit 111d40e909ce5cf507ce7d4aa81f35d947f03fe0