Please add support for GBK in ST3 Package on Windows

[07freedom]

AutoPEP8 package for Sublime Text 3 got error:

UnicodeDecodeError: 'gbk' codec can't decode byte 0x80 in position 3168: illegal multibyte sequence

when it runs into Chinese characters. One way to solve it is to add "encoding=UTF-8” in https://github.com/wistful/SublimeAutoPEP8/blob/ea8bbdd811f7987cb8106aa099fa885df8a5a9b2/sublimeautopep8lib/autopep8.py#L3959

[wistful]

Thank you for the suggestion. Sounds like an interesting feature. The package is not actively maintained right now, and I can't promise I'll look into that. However, I'm open to PRs with new features and bug fixes. Contributions and help are very welcome.