Use of ReStructuredText for docs

[kylepjohnson]

In the past I have toyed with the idea of switching to Markdown for doc strings, but was not so impressed by the tools that I wanted to switch.

Now, I see that Sphinx, the standard Python docs-building tool, handles Markdown: https://docs.readthedocs.io/en/latest/intro/getting-started-with-sphinx.html#using-markdown-with-sphinx (I hadn't seen this!). And Read the Docs, which we use for hosting our docs, presumably accepts the output.

I have seen complaints about Markdown, that it is not standardized enough (resulting in silly things like "GitHub flavored"). But for our purposes we would only need to conform to Sphinx's style. I am willing to make the switch, personally.

[kylepjohnson]

Totally loving rst and see the power of building docs out of the source. I want to use rst thorough, even for READMEs and such.