locig: refresh after edit project

* implemented saving project settings force-refreshes the project if something has changed.
* when nothing has changed while editing the project settings, the project is not refreshed anymore.
* new project window is cleared now before it is displayed.

src/lib_gui/qt/window/QtProjectSetupScreen.h

@@ -20,6 +20,7 @@ public:
 	QtTextLine(QWidget *parent);
 	QString getText();
 	void setText(QString text);
+	void clearText();
 
 private slots:
 	void handleButtonPress();