OS independence

[GreenK173]

According to pyproject.toml, this library should be OS independent. However I've found two cases where the code only works on Unix platforms but not on Windows. One was during discussion of PR #81. The other one is the use of os.sched_getaffinity in validate.py, which is only available on Unix (as mentioned at the beggining of the section in the doc).

[Teque5]

Thanks for noting this issue with windows. We can either leave a note where we manually garbage collect (specifically for this windows issue) or we can find a function that can remove the memmap file.

I wonder, does pathlib.Path.unlink() work for this problem? Generally I think we should have all our paths in this module handled by pathlib anyway, but it's just been on the to-do list. In unix unlink() will either remove the file or the softlink.