AF中自带一些Css矢量图标，使用时需要设置class，例如下面代码显示一个左箭头图标：
AF中可用的图标类名有：
addbasketbugbusycalendarcamerachatcheckclockclosecloudcssdatabasedowndownloaderrorfoldergraphheadsethearthomehtml5infojskeylampleftloadinglocationmagnifiermailmessagemicminimizenewpaperpencilphonepicturepinquestionrefreshremoverightsettingsstackstartagtargettoolstrashtvupuploaduserwarningwifi