Don't use gt function in the constructor of kiwixApp.

The `gt` function get the instance of the kiwixApp.

So we cannot call this function in the constructor of kiwixApp itself.
Move all the (complex) initialization step in another method call after
the kiwixApp is created.

src/kiwixapp.cpp

@@ -37,30 +37,6 @@ KiwixApp::KiwixApp(int& argc, char *argv[])
     m_appTranslator.load(QLocale(), "kiwix-desktop", "_", ":/i18n/");
     installTranslator(&m_appTranslator);
     
-    try {
-        mp_downloader = new kiwix::Downloader();
-    } catch (exception& e) {
-        QMessageBox::critical(nullptr, gt("error-downloader-window-title"),
-        gt("error-downloader-launch-message") + "<br><br>" + e.what());
-    }
-    mp_manager = new ContentManager(&m_library, mp_downloader);
-
-    auto icon = QIcon();
-    icon.addFile(":/icons/kiwix-app-icons-square.svg");
-    setWindowIcon(icon);
-
-    setApplicationName("Kiwix");
-    setDesktopFileName("kiwix.desktop");
-
-    setStyle(QStyleFactory::create("Windows"));
-    QFile styleFile(":/css/style.css");
-    styleFile.open(QIODevice::ReadOnly);
-    auto byteContent = styleFile.readAll();
-    styleFile.close();
-    QString style(byteContent);
-    setStyleSheet(style);
-
-
     QString fontName;
     if (platformName() == "windows") {
         QFontDatabase::addApplicationFont(":/fonts/SegoeUI/segoeuib.ttf");
@@ -88,6 +64,33 @@ KiwixApp::KiwixApp(int& argc, char *argv[])
 
     auto font = QFont(fontName);
     setFont(font);
+}
+
+void KiwixApp::init()
+{
+    try {
+        mp_downloader = new kiwix::Downloader();
+    } catch (exception& e) {
+        QMessageBox::critical(nullptr, gt("error-downloader-window-title"),
+        gt("error-downloader-launch-message") + "<br><br>" + e.what());
+    }
+    mp_manager = new ContentManager(&m_library, mp_downloader);
+
+    auto icon = QIcon();
+    icon.addFile(":/icons/kiwix-app-icons-square.svg");
+    setWindowIcon(icon);
+
+    setApplicationName("Kiwix");
+    setDesktopFileName("kiwix.desktop");
+
+    setStyle(QStyleFactory::create("Windows"));
+    QFile styleFile(":/css/style.css");
+    styleFile.open(QIODevice::ReadOnly);
+    auto byteContent = styleFile.readAll();
+    styleFile.close();
+    QString style(byteContent);
+    setStyleSheet(style);
+
 
     createAction();
     mp_mainWindow = new MainWindow;

src/kiwixapp.h

@@ -63,6 +63,7 @@ public:
     KiwixApp(int& argc, char *argv[]);
     virtual ~KiwixApp();
     static KiwixApp* instance();
+    void init();
 
     void openRandomUrl(bool newTab=true);
 

src/main.cpp

@@ -16,6 +16,7 @@ int main(int argc, char *argv[])
     QWebEngineUrlScheme::registerScheme(scheme);
 #endif
     KiwixApp a(argc, argv);
+    a.init();
 
     QCommandLineParser parser;
     parser.addPositionalArgument("zimfile", "The zim file");