Bug fixes

Fix incorrect format for exporting Quantumult VMess subscriptions.
Fix parser not recognize over-tls obfs in Quantumult X VMess subscriptions.
Fix potential compatibility issue for non-standard VMess subscriptions.
Add basic support for acquiring headers during subscription download.

src/speedtestutil.cpp

@@ -1245,6 +1245,8 @@ bool explodeSurge(std::string surge, std::string custom_port, int local_port, st
                 {
                     if(itemVal == "ws")
                         net = "ws";
+                    else if(itemVal == "over-tls")
+                        tls = "tls";
                 }
                 else if(itemName == "obfs-host")
                     host = itemVal;