logging improvements:
- Log everything to a log file instead of the console
- For users, show only errors on the console, not warnings or below
- Don't show users SlotNotReady errors in the volumina rendering thread
- Increased timeout for errorMessageFilter, and use caption to identify duplicates (not message text)
- In debug mode, show everything on the console AND the log file.
headless: Better error message if project file can't be found.