Bug#790407: rott: please show a dialog box if files are missing

[Alexandre Detiste]

> and check if they still apply to latest post-modern g-d-p? ;)

Yes, the setup.exe is supported in GDP v42.



GDP v43 will also support the "gog_rise_of_the_triad_dark_war_2.0.0.8.sh"
archive and repacking the game that was installed with this archive.

lgogdownloader integration currently only work if someone:
- has installed this tool
- has used it after buying the game and/or the cache is up-to-date

I have yet to check why "lgogdownloader --list --game
rise_of_the_triad__dark_war"
takes 3 seconds to answer; and see if this can be used instead when
the cache is not explicitly refreshed.