[boost] Boost.Atomic on Windows, patch

Hi. I have noticed that boost/atomic/detail/generic-cas.hpp is directly including Windows.h header. I consider this problematic for WinSock using applications as Windows.h automatically pulls in Winsock.h, the WinSock 1 header. This is problematic because it requires users that want to use WinSock 2 to order their include of WinSock2.h before inclusion of Boost.Atomic. At this point in time anybody serious about sockets on Windows really do not want to use WinSock 1 but version 2 instead. So I suggest the attached patch. -- VZ