detail/value_functors.hpp: Add Namespacing

value_less and value_equal are now boost::container::value_less &
boost::container::value_equal respectively.

include/boost/container/detail/value_functors.hpp

@@ -18,6 +18,9 @@
 #  pragma once
 #endif
 
+namespace boost {
+namespace container {
+
 //Functors for member algorithm defaults
 template<class ValueType>
 struct value_less
@@ -33,4 +36,7 @@ struct value_equal
       {  return a == b;  }
 };
 
+}  //namespace container {
+}  //namespace boost {
+
 #endif   //BOOST_CONTAINER_DETAIL_VALUE_FUNCTORS_HPP