Implementation of Wasserstein barycenter stuff, for average-case images and image clustering

The 3 main references I'm using are

• https://arxiv.org/abs/1306.0895
• https://arxiv.org/abs/1310.4375
• https://arxiv.org/abs/1805.11897

Run the Demo notebook (in Jupyter Lab) to see things at work. The main accomplishments are

• Average-case digits and images (like an average-case lightbulb)
• Clustering on images to distinguish lightbuls and rainbows without supervision