TODO: integrate it in YACReader
TODO: add icons for groups
TODO: add conflicts detection
TODO: fix any shortcut used in keyPressEvent
TODO: choose new default shortcuts (F5 update, F11 fullscreen, etc...)
two "comics views" added, classic (flow+table_view) and grid (based on qml/qtquick)
TODO: the views are only interchangeable in compilation time, some more work is needed for doing it in run time.
fixed reloadCovers