Blender Git Loki

Fix T91410: Make Single User operation ignores linked data-blocks.

Now 'Make Single User' will also create local copy of linked data as
needed.

IMPORTANT: Unlike with local data, this always happen, even if linked
data has only one user. This avoids e.g. cases like two local objects
sharing a same linked mesh, then when calling 'Make Single User ->
Object and ObData' on both objects, yu expect both of your objects to
get localized meshes, not one of them keeping its linked, un-editable
mesh.