Complete DocStrings

[cmlccie]

Review modules to ensure every module, function and method is documented with a complete docstring.

For Package & Modules - DocStrings should...

• Enumerate the package's or modules's exposed API; providing simple 1-2 sentence descriptions.
• Call out any notable requirements or key pieces of information when using the package / module.

For Classes, Functions & Methods - DocStrings should...

• Provide a simple 1-sentence description describing purpose / use.
• Provide a more complete description of use if needed.
• Enumerate attributes, arguments, return types, and exceptions raised.

All DocStrings should use the Imperative Tense or Mood, and should use package consistent formatting (intent is to use an auto-generation tool to assist with package documentation).

[cmlccie]

Docstrings may need to be converted to reStructuredText format for better Sphinx-autodoc support.

The existing Google-style docstrings can be used by autodoc, but we lose the ability to leverage reStructuredText features in the docstrings.

[cmlccie]

PR #47 All user-facing package APIs have been reviewed, updated and completed. Done!