Enhancements

Fix potential segmentation fault error due to some incorrect copy assignments.
Fix potential crash due to incorrect usage of cURL library.
Fix potential memory leak causing memory usage to be too high.
Add /qx-rewrite and /qx-script interface to add device ID to scripts for some version of Quantumult X.
Add policy-path parsing support for /surge2clash interface.
Add interval/strict options support for managed config.
Add filename option for setting file name when downloading exported subscriptions.
Optimize codes.

src/webserver_libevent.cpp

@@ -32,7 +32,7 @@ std::vector<responseRoute> responses;
 
 static inline void buffer_cleanup(struct evbuffer *eb)
 {
-    evbuffer_free(eb);
+    //evbuffer_free(eb);
 #ifdef MALLOC_TRIM
     malloc_trim(0);
 #endif // MALLOC_TRIM
@@ -102,8 +102,8 @@ void OnReq(evhttp_request *req, void *args)
     std::map<std::string, std::string> extra_headers;
     retVal = process_request(req_method, uri, postdata, content_type, return_data, &status_code, extra_headers);
 
-    //auto *OutBuf = evhttp_request_get_output_buffer(req);
-    struct evbuffer *OutBuf = evbuffer_new();
+    auto *OutBuf = evhttp_request_get_output_buffer(req);
+    //struct evbuffer *OutBuf = evbuffer_new();
     if (!OutBuf)
         return;
 
@@ -168,6 +168,7 @@ int start_web_server(void *argv)
 
     evhttp_set_allowed_methods(Server.get(), EVHTTP_REQ_GET | EVHTTP_REQ_POST | EVHTTP_REQ_OPTIONS);
     evhttp_set_gencb(Server.get(), OnReq, nullptr);
+    evhttp_set_timeout(Server.get(), 30);
     if (event_dispatch() == -1)
     {
         std::cerr << "Failed to run message loop." << std::endl;
@@ -253,6 +254,7 @@ int start_web_server_multi(void *argv)
 
         evhttp_set_allowed_methods(httpd, EVHTTP_REQ_GET | EVHTTP_REQ_POST | EVHTTP_REQ_OPTIONS);
         evhttp_set_gencb(httpd, OnReq, nullptr);
+        evhttp_set_timeout(httpd, 30);
         ret = pthread_create(&ths[i], NULL, httpserver_dispatch, base[i]);
         if (ret != 0)
             return -1;