Runtime fixes:

- Compilation error with Qt4 as "QUrlQuery" class was introduced since Qt5.
- Client side download code has been removed as now we support server side download.
- We should not delete sender object inside slot. If we do so it may crash the application. To avoid this, we used Qt's "deleteLater" which will delete the objects once the processing of all the events have been done.

runtime/BrowserWindow.h

@@ -98,7 +98,6 @@ private:
     void createActions();
     void pause(int seconds = 1);
     int  findURLTab(const QUrl &name);
-    bool checkClientDownload(const QUrl &name, const QNetworkRequest &request);
 };
 
 #endif // BROWSERWINDOW_H