Don't error quit if project setup dialog has invalid resources

[ioan-chera]

At least two cases identified so far:

1. Invalid resource files (other than ugh)
2. Ugh files with syntax errors

Instead of suddenly terminating Eureka, they should calmly inform the user and (depending on user experience) either request correction or skip them and close the dialog anyway.

Blocked by

• [x] #23 because we need a more robust wad system.
• [ ] #97 because we need to easily handle lifetimes of failed objects