tcpsockets: Don't pull in platform-specific headers in headers. (#26)

This pollutes the namespace for all users of these headers.
This is particularly an issue on Windows.

src/main/native/include/tcpsockets/TCPStream.h

@@ -27,12 +27,6 @@
 #include <cstddef>
 #include <string>
 
-#ifdef _WIN32
-#include <winsock2.h>
-#else
-#include <sys/socket.h>
-#endif
-
 #include "tcpsockets/NetworkStream.h"
 
 struct sockaddr_in;