Documentation fixes:

- core.hpp: hide non-public macros
- default_delete.hpp: Hide detail code
- unique_ptr.hpp: Likewise
- utility_core.hpp: Document move_if_not_lvalue_reference

include/boost/move/core.hpp

@@ -27,6 +27,8 @@
 #include <boost/move/detail/config_begin.hpp>
 #include <boost/move/detail/workaround.hpp>
 
+// @cond
+
 //boost_move_no_copy_constructor_or_assign typedef
 //used to detect noncopyable types for other Boost libraries.
 #if defined(BOOST_NO_CXX11_DELETED_FUNCTIONS) || defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
@@ -49,6 +51,8 @@
    //
 #endif   //BOOST_NO_CXX11_DELETED_FUNCTIONS
 
+// @endcond
+
 #if defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && !defined(BOOST_MOVE_DOXYGEN_INVOKED)
 
    #include <boost/move/detail/type_traits.hpp>