Code also handling auto-generation of static overrides.
Aside from some naming consistency cleanup, this commit:
* Is the first step addressing the 'operator' issue with static
overrides, by implementing a first version of the 'restore from
reference' behavior.
* Fixes several issues that were discovered on the way in enhanced
RNA comparision code, like the 'zero-length dynamic array' case, or some
infinite looping caused by some non-ID pointers (that for some
mysterious reasons did not show up previously...).
* Factorizes a bit said RNA comparison code (auto-static override
generation and comparison/check were essentially doing the same thing).