analysis of state that spans attributes

[chriseppstein]

Presently, dynamic states of an element are only able to express dynamism within the possible values for a single attribute. This works for css-blocks because all styles are passed to opticss as classnames, but css-blocks could similarly produce correlated analysis of many attributes and let opticss drive the optimization to classnames during rewrite. Other frameworks may have different ways of expressing styles that are more semantic and would be more correctly handled this way.