assigned style vs computed style

[travisleithead]

It may be good to differentiate between CSS properties assigned by the author, and whether those properties were applied in any way. For example, to support testing of what properties are/will be applied, and which are ignored by a given implementation.

[travisleithead]

For the most part, we can't identify too many scenarios where scraping the applied styles actually matter when you have full metrics information. One use case not handled is feature-detection of what styles are supported, and that should be considered.

[travisleithead]

With the addition of a FormattedTextStyle object that parses CSS, presumably only for this scenario, we could have non-relevant CSS dropped at parsing time allowing introspection of the results to help determine what CSS is supported by the implementation?

See PR #39