Implement pattern state lowest common denominator

[bmuenzenmeyer]

Summary of changes:

• Pattern States are now assigned using the pattern key (atoms-colors), not the pattern name (colors). This change aligns with other uses of the key throughout Pattern Lab.
• Patterns inherit the lowest common denominator pattern state of their lineage.
• Pattern inheritance occurs only for patterns that define a pattern state themselves.

closes #203

[geoffp]

Nice!

I am now realizing that I think we overlooked unit tests in our whitespace cleanup.

[bmuenzenmeyer]

Right - I saw that too, in addition to eslint. It's a good bit of busy work that can be put into #241