Compile fix for Visual C++ Update 3

Starting with Visual C++ Update 3 RC, WSAAddressToStringA and gethostbyaddr are deprecated.
This leads to compiler warnings which are treated as an error with the /sdl switch (which is enabled by default for new projects):

error C4996: 'WSAAddressToStringA': Use WSAAddressToStringW() instead or define _WINSOCK_DEPRECATED_NO_WARNINGS to disable deprecated API warnings
error C4996: 'gethostbyaddr': Use getnameinfo() or GetNameInfoW() instead or define _WINSOCK_DEPRECATED_NO_WARNINGS to disable deprecated API warnings

This change calls WSAAddressToStringW instead of WSAAddressToStringA for Visual C++ 2013 and later.