bpy_extras.io_utils.path_reference() expects a real dir as base_src, not the blend file name!

update addons enabled by default to use 'faces -> tessfaces' also grease pencil scatter and quake map export.

from Martijn Berger (juicyfruit) 

with some edits for efficient dict access.

from ed gautier (edddy) 

indentation edits and copy pyrimid from contrib (where I had made some edits), removed so this wont happen again.

Fix #28816: Error when importing obj file with texture due to api change

Update obj importer and xcf importer to use new post-texface api.

Plus a few styling enhancements.

[[Split portion of a mixed commit.]]

Adding UNDO flag to import operators. Made this only for trunk addons.

previous order deprecated.

- remove/comment unused variables
- remove unused imports
- fixed some bugs using incorrect variables

add tooltip to address [#27798] .OBJ Import with 'Split' option enabled, skips verts with no face/edge users.