Rewrite code for returning information about torrents as JSON (Web UI)

- The new code is simpler, cleaner and more efficient

src/qtlibtorrent/qbtsession.cpp

@@ -682,7 +682,7 @@ void QBtSession::initWebUi() {
         httpServer->close();
       }
     } else {
-      httpServer = new HttpServer(3000, this);
+      httpServer = new HttpServer(this);
     }
 
 #ifndef QT_NO_OPENSSL