安装环境：ubuntu16,python2.7
1. 安装lxml OpenSSL
sudo apt-get install python-dev
sudo apt-get install libevent-dev
sudo apt-get install openssl
sudo apt-get install libssl-dev
2. 安装并更新pip
sudo apt-get install python-pip
pip install --upgrade pip
3. 安装scrapy
pip install Scrapy
