New in this release:
1. Added UMAP projection, with docs (use `Embedding(projection="umap")`); requires `pip install umap-learn`
2. Remove status check on debounce for filter bar, in UI
3. Put a timeout on downloads (any path that is http or https)
4. Fixed two bugs in dg.read_csv(): handle no headers, if converted raises, use None value
5. Adjust the size of points in thumbnail scatter plots of embeddings
6. Updated notebook `Visualizing_embeddings_in_Kangas.ipynb`
7. Added `Embedding(scale=True)` for "umap" and "pca"