Add graceful fossil error handling

[Oliveriver]

Currently, if a player has an invalid .thrivefossil file in their fossils folder, the entire game crashes when opening the Thriveopedia. Not really ideal.

It might be better to catch this error and either skip the fossil in the museum list or have its museum card tell the player the fossil is corrupt. The latter would be much more work and to be honest, I don't think it's worth it. Just ignoring that fossil entirely should be fine.