Added latest gpt models, mistral local and mistral api

In some shells (e.g., zsh), the bracket syntax throws an error
without the quotes.

Although demo.ipynb seems to be an older version of the example code in demo.py,
let's fix up the model list so it won't throw errors when people run it.
- text-davinci-003 is deprecated, and OpenAI recommends gpt-3.5-turbo-instruct instead
- team's OpenAI account doesn't have access to gpt-4

Make sure 'parallel' is always in **kwargs and don't pass it in
explicitly when calling generate_predictions.

Referencing this iPython extension can cause errors for people
running the Jupyter notebook for the first time (some IDEs
are smart enough to prompt for an install, but some are not). Because
%autoreload isn't really useful for someone running a demo, let's
remove it.

This is an optional convenience for people who don't want to
store secrets in dotfiles such as .zshrc or .bashrc (or are
having trouble doint so).

demo_openai.py is a copy of demo.ipynb, since it will be easier for
lab meeting to collaborate outside of a notebook environment.