corrected a few typos in the readme, also provide example snippets that can run in google colab

[jeremymanning]

note: the previous snippets could run in google colab before the recent(ish) updates, but the new colab includes a version of tensorflow that is not compatible with numpy 1.20.1, so it was causing some issues. i've changed the numpy examples to use 1.23.1 instead, which fixes the examples.

similarly, some of the pandas examples depended on versions of pandas that required numpy versions that conflicted with tensorflow. the versions in the updated examples are now self-consistent and work in colab.

finally, the hypertools commit in the example was different than the explanatory text; they're now consistent.

other than that i corrected a few minor typos and changed some of the formatting.

[paxtonfitzpatrick]

Thanks! I hadn't checked those since I originally wrote them. I suppose this is going to continue happening though, as colab keeps updating its package (and Python) versions...