Initialize standard resources path at startup, not just when first file is opened.
Have the part creator object immediately tell the part who created it.
That way, no matter how we ask for a part to be created, it remembers its type. Also, since we don't have a part creator for unknown part types, make sure we don't crash when saving after encountering one.
Implement "new project" menu item. Not really happy with the term project after all.