Simplify the code that checks if it's OK to close the current file

And make sure it gets called whenever it needs to get called - it was
missing from the openRecentFile case.

Fixes #530

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-ui/mainwindow.h

@@ -169,6 +169,8 @@ private:
 	QString filter();
 	static MainWindow *m_Instance;
 	bool askSaveChanges();
+	bool okToClose(QString message);
+	void closeCurrentFile();
 	void writeSettings();
 	int file_save();
 	int file_save_as();