Add batched recv/send to WinDivert (#156).

This change allows multiple packets to be
received/sent at once, reducing overheads.  To
exploit this feature, applications need to use
the WinDivertRecvEx()/WinDivertSendEx()
functions with the new addrLen parameter.  The
passthru example has been modified to use
batching.

The DEBUG flag has been retired since it
conflicts with batching, and was not very
useful anyway.

test/test.c

@@ -319,7 +319,7 @@ int main(void)
     // (1) stop normal traffic from interacting with the tests; and
     // (2) stop test packets escaping to the Internet or TCP/IP stack.
     upper_handle = WinDivertOpen("true", WINDIVERT_LAYER_NETWORK, -510,
-        WINDIVERT_FLAG_DROP | WINDIVERT_FLAG_DEBUG);
+        WINDIVERT_FLAG_DROP);
     lower_handle = WinDivertOpen("true", WINDIVERT_LAYER_NETWORK, 510,
         WINDIVERT_FLAG_DROP);
     if (upper_handle == INVALID_HANDLE_VALUE ||
@@ -468,7 +468,7 @@ static BOOL run_test(HANDLE inject_handle, const char *filter,
         goto failed;
     }
     overlapped.hEvent = event;
-    if (!WinDivertRecvEx(handle, buf, sizeof(buf), 0, &addr, &buf_len,
+    if (!WinDivertRecvEx(handle, buf, sizeof(buf), &buf_len, 0, &addr, NULL,
             &overlapped))
     {
         if (GetLastError() != ERROR_IO_PENDING)