(ixwebsocket) add WebSocketProxyServer, from ws. Still need to make the interface better.

ixwebsocket/IXWebSocketProxyServer.h

@@ -0,0 +1,20 @@
+/*
+ *  IXWebSocketProxyServer.h
+ *  Author: Benjamin Sergeant
+ *  Copyright (c) 2019-2020 Machine Zone, Inc. All rights reserved.
+ */
+#pragma once
+
+#include "IXSocketTLSOptions.h"
+#include <cstdint>
+#include <stddef.h>
+#include <string>
+
+namespace ix
+{
+    int websocket_proxy_server_main(int port,
+                                    const std::string& hostname,
+                                    const ix::SocketTLSOptions& tlsOptions,
+                                    const std::string& remoteUrl,
+                                    bool verbose);
+} // namespace ix