Support lowering single-arg psuedoclasses.

Implement psuedoclass rewrite rules.

Substitute in counters for any CSS textual property, not just `content`.

Will be required by Rhapsode for navigational markers.

Implement whitespace collapse, togglable via white-space: pre/normal;

Parse & prepare to handle white-space: pre;

Implement CSS3 counters.

Parse CSS counters.

Fix compilation of Assets StyleSheets.

Provide utilities for rewriting CSS-referenced URLs.

Improve documentation, release version 1.2

Write reference documentation.

Request @import'd styles concurrently.

Let user & useragent styles query for a lack of author styles.

Introduce simplified html2css API

Which, now that these are implemented, lowers <style> to @media & <link rel=stylesheet> to @import.

Unittest conditional styles, add loadImports API to fit Rhapsode's use.

Test rules capturing of ConditionalStyleSheet.

Fix: ConditionalStyles reversed CSS precedance.

Fix precedence of conditional blocks (+API redesign)

Implement @supports.

Draft interpretor for @supports.