add unread red dot for voice
Merge pull request #152 from chenweiyj/master

添加语音信息未读小圆点标记
1.添加语音为查看的使用方法  2.整理代码结构
Update README.md
Merge pull request #156 from lzwjava/patch-2

typo
add isMaxTimeStop to avoid send the message twice both on max time exceeded and hold down button triggering touchupinside event
Merge pull request #158 from chenweiyj/master

增加判断是不是超出了录音最大时长以避免发送语音两次