docstring update

[ConnorStoneAstro]

It would be great for all caskade classes and methods to have detailed docstrings. I would like them to be numpy style, including the short description, long description, parameters (if appropriate), returns (if appropriate), and concise example usage. It would be good to match up the example usage with the Jupiter notebook tutorials where possible. We would also need to update all the existing docstrings since some might have fallen out of sync.

Further, for the website it would be great if the autodocs could be put into a nicer organization. Right now they are just all clumped together in a way that is hard to navigate.