To install python-zcashlib for testing and editing, clone the repository to your local filesystem. It is currently on a branch of python-bitcoinlib maintained by @arcalinea.
Then, install the module locally in editable mode through pip, so that you can make changes to the code of python-zcashlib and they will be applied immediately. It is necessary to install python-zcashlib this way for now because the fork of the library likely contains many bugs, which need to be fixed before `zec-p2sh-htlc.py` will work properly.
`protocol-pseudocode.py` is guaranteed to not run. It was written as a brainstorm/sketch of a hypothetical xcat protocol using @ebfull's fork of Zcash/Bitcoin that supports createhtlc as an rpc command. Including here in case it's useful in any way.
I used the module [future](http://python-future.org/futurize.html) to make existing python2 code for the rpc interface compatible with python3.