add new message type
add new message type

微信自定义菜单中的链接被点击后会向微信服务发送一个 `view` 类型的事件
参考链接： http://mp.weixin.qq.com/wiki/index.php?title=%E8%87%AA%E5%AE%9A%E4%B9%89%E8%8F%9C%E5%8D%95%E5%88%9B%E5%BB%BA%E6%8E%A5%E5%8F%A3
Infixz/WeRoBot,FlyRabbit/WeRoBot,tdautc19841202/WeRoBot,adam139/WeRobot,FlyRabbit/WeRoBot,whtsky/WeRoBot,Zhenghaotao/WeRoBot,weberwang/WeRoBot,adam139/WeRobot,adrianzhang/WeRoBot,chenjiancan/WeRoBot,notwin/WeRoBot,Zeacone/WeRoBot,kmalloc/WeRoBot,weberwang/WeRoBot,one-leaf/WeRoBot,whtsky/WeRoBot,whtsky/WeRoBot