D-7

v-4.0
---
1. New Class => WavFile.java

	==> done
D-7

v-4.2
---
1. R channel, L channel => to different buffers

	==> done
D-7

v-4.3.0
---
1. plot => try 1

	==> done
D-7

v-4.3.1
---
1. plot => try 2

	==> done
D-7

v-4.3.2
---
1. plot => a.wav

	==> done
D-7

v-5.0
---
1. wave => png

	==> done