[Qt-interest] close app before exec()

[Martin Gebert]

>    2. Set a flag (boolean member) in your constructor on success of the
>       initialization, reimplement QMainWindow::exec() for your main
>       window class and return with the appropriate return code if the
>       initialization failed.
>   

Or, better yet, delay the part of the initialization that may fail and
move it into exec() at all.

Martin