[boost] [date_time, asio, range] Unused argument warning fixes

Attached is a patch against the SVN trunk that fixes several unused argument warnings from gcc. With one exception the changes are just commenting out the argument name in the function definition. but there is a more ugly fix in <asio/detail/strand_service.hpp> that is only required when building with NDEBUG defined (e.g. when assert is a noop). Can the owners of the code take a look and either commit the appropriate fixes or give me the go-ahead to do it myself. I don't want to step on any toes. -- Caleb Epstein