Improve py -> ipynb conversion

BLcourse2.3/convert-to-ipynb.sh

 #!/bin/sh
 
+# Remove plots etc, but keep random cell IDs. We need this b/c we use jupytext
+# --update below.
+nbstripout --keep-id *.ipynb
+
 for fn in 0*dim.py; do
+    # --update keeps call IDs -> smaller diffs
     jupytext --to ipynb --update $fn
 done

BLcourse2.3/requirements.txt

@@ -30,4 +30,10 @@ jupyter
 # or Jupyter notebook is also fine
 ##notebook
 
+# ----------------------------------------------------------------------------
+# dev
+# ----------------------------------------------------------------------------
+
+nbstripout
+
 # vim:syn=sh