Pytvpaint

* UPDATE clip json export to handle all options (fill_bakcground, all_images, etc...)
* [BREAKING CHANGES] UPDATE tv_clip_save_structure_json default values

Updates and Features:

- Updated documentation
- Added new functions in Layer class : render and render_instances
- Clamp values for position to minimum 0
- Updated `get_` functions in classes to return None instead of raising an error when element not found
- Update tests

Fixes:

- Fix layer position not setting position 0 correctly
- Fix mark_in/mark_out not set correctly

Breaking Changes :

- Updated function signatures and default values for :
- Clip.load_media
- Clip.render
- Clip.export_json
- CLip.export_psd
- Clip.export_csv
- Clip.export_sprites
- Clip.export_flix
- Clip.set_layer_color
- Layer.render_frame
- Project.render
- Project.render_clips

* FIX client auto-connect not working properly
* FIX background colors set in Project class

Changed

- Change `tv_background_set` George function signature to accepts a single color argument of type `tuple[RGBColor, RGBColor] | RGBColor | None` to be coherent with `tv_background_get`. 9

Features :

- ADD background mode option in render functions
- UPDATE background mode and color functions in API

Fixes :

- FIX render context setting save mode instead of alpha mode

Thanks to Kim Strandli for reporting this 👍

Features:

* ADD new functions to Layer and LayerInstance
* ADD new functions and properties to make range handling easier


Fixes:

* FIX misc issues with rendering
* FIX and UPDATE documentation