Update to python 3.13

[clemens-fricke]

Yesterday I was notified by a colleague that splinepy has some issues in python 3.13. We are not currently supporting 3.13 so there is no inherent problem, but you can still install it into a 3.13 environment if you want, but a few things won't work until we have addressed these issues.

If you notice any issues, please report them here.

I have not made a deep dive into what all fails, but currently, I am aware of the following issue(s):

1. class properties (like in TileBase) are not supported anymore. So microtiles are currently broken in 3.13. I am not sure if we used this anywhere else.