@BarryThePenguin did a fantastic job in #90 adding near 100% code coverage in one swoop. Thanks!
We also decided that the old body/header gray value & hue API was... confusing. That's not how most people think about the color of text. So now there's just bodyColor and headerColor. Also per @bvaughn suggestion in #92, headerColor defaults to 'inherit' so it's simpler to override header/body font colors together.