Add support for transformations

[bodoni]

Add support for transformations

[dustdfg]

I just want to add that stored transforms must be a list Vec<Transform> because svg allows several different transforms at the same time: translate(100 100) scale(0.5 0.5). Also the API should be not element.transform(transform: Transform) but rather element.transform(transform: Transform, squash: bool) because user can want to get one matrix after several transforms and not a list of transforms

P.S If you want to know when the list of transforms is more preferable than matrix:

1. The svg is suited for people reading/editing
2. You can easily emulate transfom-origin property from svg2 via several sequential transforms

[IvanUkhov]

Hello, yes, indeed. There is no higher-level interface for doing this. I myself use exactly the approach you described. Since for constructing data for paths we have it, it could make sense to have it for transformations too.

https://github.com/bodoni/svg/blob/main/src/node/element/path/data.rs