See ExCSS pull request #62: https://github.com/TylerBrinks/ExCSS/pull/62

- Support of generic fonts (serif, sans-serif, monospace)
- Initial support of filters
- Fixes to gradient rendering

- Very initial support of CSS stylesheets in the SVG via including the
ExCss and Fizzler libraries
- Bug fixes with path rendering
- Improvements to the API for loading an SVG file