adjustments necessary to run `open_ended_coders.py` outside of Docker

[18kimn]

For some reason running docker compose up exits immediately with no error for the mpeds service, and running docker build . -f Dockerfile while in the mpeds subfolder also fails (although the error is taking a really long time to pop out now)

This PR just demonstrates the adjustments I made to get the script working outside of the docker environment; I'm not suggesting changes in any way, just putting this up to show what I did for docs purposes. Feel free to close after you've seen it --

Most of the edits had to do with migrating to python3, but there were some cases where the existing parser wanted to see a subject following a number, e.g. three hundred demonstrators, and would refuse to code three hundred on its own properly. I believe students were not aware of this requirement and in general articles don't always follow the structure of (number)(subject), so sometimes they would say "the number of demonstrators totaled three hundred" or any other form. So I removed the requirement for this token pattern

[alexhanna]

Thanks. Tagging this with #15, because most of the changes are Python 3 ports.