本文基于环境：win10(64)+python3.6(64)
第一次直接pip install scrapy，安装出错，错误提示
error: Microsoft Visual C++ 14.0 is required. Get it with "Microsoft Visual C++ Build Tools": http://landinghub.visualstudio.com/visual-cpp-build-tools
于是，我登陆网站http://landinghub.visualstudio.com/visual-cpp-build-tools，下载Visual C++ build tools 2015，并安装。
安装上述Visual C++ build tools 2015之后，再pip install scrapy，就搞定了！
