修改pip源
http://www.cnblogs.com/hushaojun/p/4606986.html
mkdir -p ~/.pip/
vi ~/.pip/pip.conf
[global] trusted-host=mirrors.aliyun.com index-url=http://mirrors.aliyun.com/pypi/simple/
- http://pypi.v2ex.com/simple/
- http://pypi.douban.com/simple/
- http://mirrors.aliyun.com/pypi/simple/