The following is from the original commit in the 4.x branch:
Reuse QFileDialog to implement the FileDialog desktop component.
old change-Ids: I9d64a87dd1885f298b2d7db690e4a26de3a2fb70
which was written by Alberto Mardegan <mardy@users.sourceforge.net>
and Ic4aac60ad1dcad7fc9c10caea36a6abd84ee6ce1
Make the TopLevel.qml File menu show a file dialog.
Also borrowed a couple more Tango icons for the Gallery example.

Change-Id: Ia5abb2a0ae432e03fcbe46a7f682e891537593ab
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@nokia.com>