Vtracer

* Update `visioncortex` version to `0.8.8`

* New converter API https://github.com/visioncortex/vtracer/pull/59

* Fixed "The two lines are parallel!"

Python Binding

Thanks to the contribution of [etjones](https://github.com/etjones), we now have an official Python binding! https://github.com/visioncortex/vtracer/pull/55

* Handle transparent png images (cli) https://github.com/visioncortex/vtracer/pull/23

* SVG path string numeric precision