Warn users about non-liability of original authors

[qnighy]

It's good to warn users that the original authors of RGSS and the games have nothing to do with problems caused by tapir. I'd like to show messages like the following:

Warning: if you have a problem playing this game, DO NOT ASK ENTERBRAIN OR THE AUTHOR OF THE GAME. Most of the problems you will encounter are caused by tapir. Instead, we appreciate you file the issue to tapir developers.

It would be good to show this message at launch and when an error is raised.