os.add_dll_directory does not work as expected on Windows with anaconda

[lucask07]

Could not import ok when using Windows and anaconda 3.9.7
Similar issues seem to have been noticed by the scipy community:

• ddl_add_directory issues

In addition add the DDL directory to the path using:

    os.environ.setdefault('PATH', '')
    os.environ['PATH'] += os.pathsep + dll_dir

As explained at the bottom of this issue

[Ajstros]

Fixed with #12