scratch all car picture from one website,爬取一个网站内，某一栏目的汽车图片
this is my first spider ,so there are so many things need to be finished,and also there so many disadvantage need to be corrected ,so i hope you can message me how to improve this code,thanks,email me：hiveme@163.com
第一个爬虫，还有好多问题需要修改，欢迎大家提出宝贵的修改意见，邮箱：hiveme@163.com