first step to decode J8R files

[tengel]

This is a first step towards decoding J8R files.
I started with the command line from #3 from @AL1-1956.

It seems there is a 56 byte header (we can skip now with -s) and the cluster size is 1024k.
But there are still some issues:

• We have to specify a sampling frequency of 88200 Hz which should probably 44100 Hz.
• The output contains still some noise. It would be nice to have a plain sine or triangle signal in J8R format to figure out what is wrong.