[boost] Enabling fast swap optimization for Boost types VC9 SP1.

The VC team recently released an update to the VC9 standard library that allows them to take advantage of types with fast swap when performing operations like vector realloc. However it appears this optimization is guarded by a trait that must be specialized. Could we specialize std::_Move_operation_category for this version of VC9 to enable this optimization for boost types that can benefit from it? http://tinyurl.com/6h298c Thanks, Michael Marcin