Add what's new dialog

YACReaderLibrary/images.qrc

@@ -123,5 +123,7 @@
         <file>../images/updatingIcon.png</file>
         <file>../images/useNewFlowButton.png</file>
         <file>../images/useOldFlowButton.png</file>
+        <file>../images/custom_dialog/custom_close_button.svg</file>
+        <file>../images/whats_new/whatsnew_header.svg</file>
     </qresource>
 </RCC>

YACReaderLibrary/library_window.cpp

@@ -83,6 +83,8 @@
 
 #include "trayicon_controller.h"
 
+#include "whats_new_controller.h"
+
 #include "QsLog.h"
 
 #ifdef Q_OS_WIN
@@ -104,6 +106,15 @@ LibraryWindow::LibraryWindow()
         showRootWidget();
         selectedLibrary->setCurrentIndex(0);
     }
+
+    afterLaunchTasks();
+}
+
+void LibraryWindow::afterLaunchTasks()
+{
+    WhatsNewController whatsNewController;
+
+    whatsNewController.showWhatsNewIfNeeded(this);
 }
 
 void LibraryWindow::setupUI()

YACReaderLibrary/library_window.h

@@ -405,6 +405,8 @@ public slots:
     void prepareToCloseApp();
     void closeApp();
 
+    void afterLaunchTasks();
+
 private:
     //fullscreen mode in Windows for preventing this bug: QTBUG-41309 https://bugreports.qt.io/browse/QTBUG-41309
     Qt::WindowFlags previousWindowFlags;