Add support for viewbox transformations for intrinsic raster image dimensions

[EugeneBalabai]

This PR provides solution #284

Changes

• Modified ImageNode to use computeViewBoxTransform for handling image scaling and positioning
• Images now properly respect the SVG preserveAspectRatio attribute

[EugeneBalabai]

1. Some tests are failing, though visual inspection shows correct output. The failures appear to be related to how transformations are being applied.

2. Is there an alternative approach to obtain accurate image dimensions?

[EugeneBalabai]

@yGuy @HackbrettXXX What do you think?

[yGuy]

I currently don't have the time to debug this or do a new implementation. Sorry!
@HackbrettXXX is also busy, but he might have a quick answer for you, at least.

[HackbrettXXX]

If the visual output looks good, you can probably just update the reference files. You can download them from the CI build result.

The approach for obtaining the image dimensions looks good. Although I would love if we would have to load the image only once (-> fetchImage).

I hope I have time for an in-depth review soon.

[HackbrettXXX]

Looks good. I've added/changed the reference files. Loading the image only once is probably not feasible, because of the special case for SVG images.