( #754) Implement transform property
This aims to add transform property (leaving the attribute alone) for CSS Transforms in SVG 2.
Current Progress:
Parsers: Done
Tests for Parsers: Done
ComputedValues: Done
Then modifying the shapes to take the new property into account: Should be done automatically since it resolves to a transform.
Reference test: Needed
The current iteration of the code renders the image from #487 (closed) (found here) exactly as firefox does. But rough tests with making a file with the same transforms in the attribute grammar didn't produce the same efects, which I think is because the CSS composition of the matrices is simply "multiply them from left to right" rather than the same pre/post system from the attribute, but it needs more testing before being considered done.