Break down complex method

Break down the complex method `TempoSyncBarModelEditor::updateDescAndIcon` by delegating to the new methods `updateTextDescription` and `updateIcon`.

include/TempoSyncBarModelEditor.h

@@ -73,6 +73,11 @@ protected slots:
 	void showCustom();
 
 
+private:
+	void updateTextDescription();
+	void updateIcon();
+
+
 private:
 	QPixmap m_tempoSyncIcon;
 	QString m_tempoSyncDescription;