title: Standard "About" dialog in Qt
body: <p>What's the standard way to implement an "About" application dialog in Qt? You know, the kind that pops up when you go Help > About... from the application menu.  I'm using Qt Designer to layout my main window, but I don't need anything fancy. It would be nice to do it in 2 lines of code instead of creating a new class or a new form in Qt Designer...</p>