fix close bug and tests : let poll do his job when closing (#79)

* let poll do his job when closing

* try fix test

* try fix test

* Update IXWebSocketTransport.cpp

* add log to find issue on CI

* add log to find issue on CI

* add log to find issue on CI

* add log to find issue on CI

* add log to find issue on CI

* change state immediately, and send close frame after

* add immediate close test

* disable test for windows

ixwebsocket/IXWebSocket.cpp

@@ -293,8 +293,8 @@ namespace ix
                 break;
             }
 
-            // We cannot enter poll which might block forever if we are stopping
-            if (_stop) break;
+            // We can avoid to poll if we want to stop and are not closing
+            if (_stop && !isClosing()) break;
 
             // 2. Poll to see if there's any new data available
             WebSocketTransport::PollResult pollResult = _ws.poll();