Function docstring standardization

It seems like we have a few different docstring styles in the code. I'd like to standardize around one format as a standard.

I found this article on some different standards/options:

https://stackoverflow.com/questions/3898572/what-is-the-standard-python-docstring-format

Of these I'm not picky, except to say I'm not super into the Epytext/Javadoc style. I do like the readability of numpydoc.

If we can decide on this, I'll take it on to port over existing docstrings.