append MessageEvent receive example
append MessageEvent receive example

Aoyunyun/jpush-docs,raoxudong/jpush-docs,xiongtiancheng/jpush-docs,xiongtiancheng/jpush-docs,raoxudong/jpush-docs,xiongtiancheng/jpush-docs,raoxudong/jpush-docs,jpush/jpush-docs,jpush/jpush-docs,raoxudong/jpush-docs,jpush/jpush-docs,Aoyunyun/jpush-docs,jpush/jpush-docs,xiongtiancheng/jpush-docs,Aoyunyun/jpush-docs,Aoyunyun/jpush-docs