This file also has insanely long object names etc. So added a generic
way to handle names for Blender data (IDs, but also non-ID data like
customprops names, UVLayers, etc.), by truncating names and adding seven
digits from their sha1 hash to their end.

Not sure how much an issue name collisions would be here, but in doubt
that should not hurt.

Too complex/risky of a change to add that one to 2.79a, though.