Various enhancements, fixes and samples:
- Support image conversion
- Define "frame" inside AVG instead of exposing as a paramter
- Add a step to flatten unnecessary nested groups
- Draw the rect from top right instead of top left
- Add warning for cases when alpha locations are not equal to color locations
- Fix matte transform bug
- Remove incorrect ellipse start/end conversion
- Fix ClipPath parsing bug
- Add support for alpha values in colors
- Add @babel/plugin-proposal-class-properties to fix build