[Interest] QFileInfoList inheritance producing warnings

[Guido Seifert]

> Well, you _can_, as long as you only add methods and no members. Qt does it too, with QQueue and QStack for instance. 
> It can be convenient to add some nice API.

You can, but you should not. Convenient can also be interpreted as lazy. ;-)
I would use a composition approach. Deemed to be more flexible. Why 
inheritance was used in QQueue and QStack? Simpler code? Better readability? 
Performance reasons? No idea. If someone can give a reason, it is probably
Thiago. :-D

Guido