ran the updateprojectfile tool on all test scenes.
the normalizeallprojectfiles.py script becomes updateallprojectfiles.py.
fixed regression.

fixed regression introduced in eb2f0503a2a36f0c20c45b9b98f42f7d34a694c8 ("automatically update project files on loading in appleseed.studio"): loading an invalid project file would crash appleseed.studio.