Improve documentation

[Techcable]

The doc comments are suboptimal, and some are missing.

We should auto-generate HTML documentation using pdoc. It looks like readthedocs supports custom build systems so we don't have to use Sphinx.

[Techcable]

Partially fixed by 7fdfb6e in v0.1.6. Although the documentation is much better, we still aren't generating and publishing API documentation.

See PR #4 for my current attempt to resolve this (pdoc seems qwirky).