七牛云图片加载优化

+'?imageView2/2/w/80'

　　https://developer.qiniu.com/dora/manual/1279/basic-processing-images-imageview2

'?imageView2/1/w/80/h/80'

　会裁剪

'?imageView2/3/w/80/h/80'
不会裁剪