Remove global CSS

[paf31]

• the CSS should generate unique class names to prevent possible conflicts with UI elements that aren't a part of this library
• should be more type safe, both in style definition and the attaching of styles to components

[dwhitney]

I like what you guys are doing with JSS. What do you think about peeling it off into a separate library?

[maddie927]

I think that'd be great, though it's very very rough at the moment. The current implementation is essentially just an unsafeCoerce, which probably doesn't merit its own library.

I'd like to figure out a better means of applying types to both the definitions and the way it's attached to DOM elements. That overlaps a lot with the efforts in https://github.com/dwhitney/purescript-react-basic-native though, and it might be easier to integrate with React as Styled-Components/Emotion types..