This is no longer necessary, see: T98554.

See T95597

Differential Revision: https://developer.blender.org/D5240

Addresses new behavior of object.to_mesh().

This is corresponding part for D4875.

Reviewers: brecht

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D4876

Mainly search-and-replace approach.

Tested the enabled-by-default export/import addons. Seems to work with
an exception of X3D which is still referencing Blender Internal material
properties.

Reviewers: brecht

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D4866

Changed objects.link and objects.unlink from scene to collection

make addons blender versions consistent

    also fix error check and report the message rather then print it.

- remove unused imports
- remove/comment unused vars
- fix for some bugs with unused vars being used

update_tag() tags for depsgraph update only, update() executes normal recalculation and creates edge data.

Removed the "Duplicate and flatten" button from modifiers and added to to the shape_key specials dropdown like the others.