Include list in rule expansion, refactor data structures test
Media queries must be explicitly marked

Assuming that arbitrary meta data supposes a media query is a terrible
idea. A data structure such as `'({:a 1})` might contain the meta data
`{:line 1, :column 8}`, for example. This could lead to confusing
results when the stylesheet is rendered.

To avoid this media queries must be explicitly marked with `^:media` or
`^{:media true}`.