Doesn't properly support Composition & Dependencies

[goodguyry]

When composing a class, the composed classname is added to the JSON mapping. Because it's one string, the helper functions aren't properly formatting the return values.

I noticed this just now with getComponentSelectors, but I'm sure the others are affected by this oversight as well.

Given the following:

/* theme.css */
.btn {
  border: 1px solid;
  color: red;
}

/* header.css */
.wrapper {
  composes: btn from 'theme.css';
}

{"header":{"wrapper":"header__wrapper___2JY86 theme__btn___2TPiI"}}

The output from getComponentSelectors

const selectors = getComponentSelectors('header');
// '.header__wrapper___2JY86 theme__btn___2TPiI'