We now follow the "update a style block" algorithm from the HTML spec
instead of using the ad-hoc CSSLoader mechanism.
This necessitated improving our StyleSheet and CSSStyleSheet classes as
well, so that's baked into this commit.
This patch adds bindings for the following objects:
- StyleSheet
- StyleSheetList
- CSSStyleSheet
You can get to a document's style sheets via Document.styleSheets
and iterate through them using StyleSheetList's item() and length().
That's it in terms of functionality at this point, but still neat. :^)
