Consider adding support for further transformations for IIIIF georeferenced map download #560
Description
Currently we only support polynomial order 1 transformations when downloading IIIF georeferenced maps. It should be fairly simple to add in support for other transformations in the future now that allmaps supports these.
This could be done either by converting allmaps transformation code to python code or using the allmaps API to do the transformation for us then downloading the result.
At the moment this is limited to polynomial 1 in the iiif_downloader.py code.