[boost] [1.53.0 beta] [type_traits] is_POD

Hi, all! I found out that Boost.TypeTraits defines a metafunction called is_POD that is essentially a template alias of is_pod, but it isn't documented.  In particular, the documentation needs to mention that is_POD must be overridden in the same cases that is_pod must be overridden. Cromwell D. Enage