Changelog of Qt5Gtk2

----------
Version 0.1
* inital release

Version 0.2
* removed gconf dependency
* removed warning about missing GtkRange::activate-slider property
* updated copyright and documentation

Version 0.3
* using gtk2 library directly
* removed unused code

Version 0.4
* added Qt 5.8 support

Version 0.5
* fixed documentation
* fixed 'distclean' target
* fixed gcc warnings
* fixed QDockWidget icons (Qt 5.10+)

Version 0.6
* show shortcuts in context menu (see QTBUG-69452)
* replaced deprecated functions

Version 0.7
* fixed Qt 5.15 support

Version 0.8
* Added preview support to the file dialog (Ilya Fedin)