Documentation

[bnels]

We should have some better documentation in this repository on:

1. How to set up configuration files (and options)
2. High level functions (and models)
3. How to add/extend to the repository

I think (1) and (3) are known by some, but not well documented. Maybe best to do this in README.md
(2) really needs to be done (when the code is first written) in a docstring.

Minimally, the docstrings should include:

1. A brief description of what the function does
2. A description of the inputs
3. A description of the outputs
4. any assumptions the function makes (optional)
   Better yet, we should have a standardized template for this.

Yes, this should be done for the models and important functions. No, this shouldn't be required of short helper functions (but it's always nice).

[bnels]

Some progress made in #13.
README.md now has a skeleton
added contributing.md to give some guidance on docstrings.

Still more to do...

[Temigo]

I will do my best to follow the Numpy conventions for docstrings:
https://numpydoc.readthedocs.io/en/latest/format.html