W2D3 - tracking changes

Notes

.aTutorial 1 contains tons of text. Could put a few parts into Bonus Reading sections, in order to keep as much as possible. E.g. ### A note on exponential growth in a bounded system
.bpyworld plots need rotation of ticklabels to allow readability
.i https://github.com/cvanwynsberghe/pyworld3/blob/main/pyworld3/utils.py  need to copy plot_ function and adjust it