Rebase Google Colab version (Jan 2020)

[0xB10C]

This rebases the changes from the last three month to the Google Colab version of the notebooks which were added in https://github.com/bitcoinops/taproot-workshop/pull/157.

[0xB10C]

Links to the rebased notebooks on Colab (only for review, don't need to change in master):

• https://colab.research.google.com/github/0xB10C/taproot-workshop/blob/2020-01-colab-rebase/0.1-test-notebook.ipynb
• https://colab.research.google.com/github/0xB10C/taproot-workshop/blob/2020-01-colab-rebase/0.2-elliptic-curve-math.ipynb
• https://colab.research.google.com/github/0xB10C/taproot-workshop/blob/2020-01-colab-rebase/0.3-tagged-hashes.ipynb
• https://colab.research.google.com/github/0xB10C/taproot-workshop/blob/2020-01-colab-rebase/1.1-schnorr-signatures.ipynb
• https://colab.research.google.com/github/0xB10C/taproot-workshop/blob/2020-01-colab-rebase/1.2-musig.ipynb
• https://colab.research.google.com/github/0xB10C/taproot-workshop/blob/2020-01-colab-rebase/2.0-taproot-introduction.ipynb
• https://colab.research.google.com/github/0xB10C/taproot-workshop/blob/2020-01-colab-rebase/2.1-segwit-version-1.ipynb
• https://colab.research.google.com/github/0xB10C/taproot-workshop/blob/2020-01-colab-rebase/2.2-taptweak.ipynb
• https://colab.research.google.com/github/0xB10C/taproot-workshop/blob/2020-01-colab-rebase/2.3-tapscript.ipynb
• https://colab.research.google.com/github/0xB10C/taproot-workshop/blob/2020-01-colab-rebase/2.4-taptree.ipynb
• https://colab.research.google.com/github/0xB10C/taproot-workshop/blob/2020-01-colab-rebase/2.5-huffman.ipynb
• https://colab.research.google.com/github/0xB10C/taproot-workshop/blob/2020-01-colab-rebase/3.1-degrading-multisig-case-study.ipynb

[jnewbery]

Thanks for this @0xB10C. I've pushed your new branch directly to the Colab branch.