Blender Git Loki

Hacky code just to try RNA_struct_dynamic_override_apply

It is crashing now, I tried either adding a scene setting (EEVEE AO), or
object settings (ob.color).

This also shows a few problems:
* We can't simply tag Scene to update when changing an override set, we need
the tagging to flush down to the scene objects.

* For scene settings we may want to do at this moment in COW evaluation, however
for objects the implementation is a bit more tricky. Because we need to change
the data owned by the object as well. For example, the material.

* In this case it is almost as if we want a cow-cow ID (the OVERRIDEN id should be
shared by all the objects that are being overridden.

* Also the affected collections thing is to be handled somehow.