python虚拟环境配置

1. install pip
- goto[pip](https://pip.pypa.io/en/latest/installing.html)develop页面，download get-pip.py
- python get-pip.py --proxy="[user:passwd@]proxy.server:port"
2. install virtualenv
- pip install virtualenv
3. create virtual environment
- mkdir xxx
- virtualenv xxx
- script ./bin/activate
4. install numpy, PIL, scipy
- pip install numy
- pip install PIL(如果找不到PIL，就用pip install pillow，这是PIL的fork)
5. install matplotlib
- brew pkg-config [mac]
- pip install matplotlib
6. install ipython
- pip install ipython