Blender Git Loki

PyAPI: use PYTHONUTF8/Py_UTF8Mode on all platforms

System encoding issues have been a paint-point for us with Python 3,
since Blender always uses UTF-8 which might not be the case for the OS.

While the Py_SetStandardStreamEncoding was already set to utf-8,
the file-system could still have an incompatible encoding.

See PEP-540 for details.