[BUG][EDITOR] Editor needs to fail more cleanly

[namida]

Currently, if anything goes wrong while loading a level or style, the user is bombarded with error messages. This needs to be changed to a single clean error message.

Better yet: If the editor encounters an error while loading a level, it should first ask NeoLemmix to cleanse the level (if a copy of NeoLemmix is present) and try to load that. Only if this fails too, it should start showing error messages.

[Gronkling]

I've been getting this problem a lot when trying to get back into using the editor after a few years.