Fetch valid chinese proxies from publishers
获取并验证中国代理服务器，方便访问大陆地区资源
Proxy Anonymity Levels
- Transparent (Level 3)
- Anonymous (Level 2)
- Elite (Level 1)
Resources:
1. [sudo -H] pip install -r requirements.txt
2. update app/settings.py if necessary
3. ./main.py
4. check out/proxies.txt, format "[level]ip:port latency"