tinyalsa: a small library to interface with ALSA in the Linux kernel

1.修改过tinyplay，可以播放带有fact部分的wav文件(在软件处理过的wav文件中经常存在)。
2.使用build.sh进行编译，生成tinyplay和tinymix

3.soundinclude 为内核里面的头文件，这个是在cscope的时候，分析代码用的。
4.include里面是需要在编译的时候包含的头文件，取自android系统

The aims are:

- Provide a basic pcm and mixer API
- If it's not absolutely needed, don't add it to the API
- Avoid supporting complex and unnecessary operations that could be
  dealt with at a higher level