v0.31.0

Changes

• Add basic radialGradient support. It's not quite perfect yet.
• Add text-decoration: underline support
• Make href synonymous with namespaced attribute xlink:href

Fixes

• Allow "use" of elements that are defined lower in the document than where they're used
• Respect fill property on the top-level svg element
• Follow href on gradient to reference parent stop definitions
• Support highly compressed path elements
• Fix crash when opacity was configured but no content was drawn