fix #541 allow loop() to be called before begin()

src/WebSocketsClient.h

@@ -91,12 +91,12 @@ class WebSocketsClient : protected WebSockets {
     void enableHeartbeat(uint32_t pingInterval, uint32_t pongTimeout, uint8_t disconnectTimeoutCount);
     void disableHeartbeat();
 
+    bool isConnected(void);
+
   protected:
     String _host;
     uint16_t _port;
 
-    bool isConnected(void);
-
 #if defined(HAS_SSL)
     String _fingerprint;
     const char * _CA_cert;