IPython in a Blender

This starts Blender (potentially under xvfb) and allows for interactive computing inside of JupyterLab.

Based on:

• https://github.com/akloster/blender-asyncio

Features:

• installable kernelspec(s)
• kernel icons
• runs on linux desktop with Blender
• synchronized object selection
• initial updating of a scene tree with ipytree
• simple float sliders
• simple, slow rendering as a static png
• runs in binder with xvfb
• in-browser interactive preview with pythreejs
• adding objects
• textures
• property viewer with ipysheet or ipytree
• vnc pass-through with jupyter-desktop-server