- Fix the bug that clean up code not called on exit
- Version bump

- Cause: Baidu will give error {'error_code': 31061, 'error_msg': 'file already exists'} for multiprocess upload as the intermediate directories are being created almost simultaneously.
- Fix: Retry on error 31061 (previously, we don't retry)

Accommodate Python 3 on Windows (threading.TIMEOUT_MAX is a little bit more thant 49 days, so set multiprocess timeout to 49 days). Close #374

Print instructions fixing 'multiprocess' erros; Properly disable urllib3 warnings; Close #345 , Close #371