v2026.0.0

Implementation and tests for Texture (#20)

* implementation and tests for Drawingelement

* initial texture class and tests

* implement average_color, filename, image_height, image_width

* add image_rep to not_implemented

* add ImageRep

* update sketchup.c

* fix typo

* texture_valid?

* add write

* update README

* add removed check

* add missing text for image_width

* remove tab

* add width and height

---------

Co-authored-by: Anton Chalakov <anton.chalakov@chaosgroup.com>
Co-authored-by: Noel <37342147+noelwarren@users.noreply.github.com>