Animations files on Windows include absolute paths

[PeterJCLaw]

Describe the Bug

On Windows (but not on Mac OS or Linux) the HTML files created to host exported animations contain absolute paths for the local machine on which they are created, for the folder in which they are created (e.g: C:\Users\Peter\Somewhere\match-13.css). This makes the files tightly coupled to that folder and machine.

Expected behavior

It would be great if the Windows animation exports contained relative paths, just as on other platforms, so that they were portable even just on the same machine or perhaps to being hosted elsewhere.