iphone发送短信，不弹出短信界面，要用到私有类，针对越狱手机。-send short message without UI, by private class ,so as for jealbreak iphone

来自黑马28期，第二天的培训内容，主要讲了消息发送器的实现-From dark horse 28, the second day of training, mainly about the implementation of the message sender