Prepends a wav header in front of a file and save it as a new file e.g. if the input was somefile.png it will generate a new file somefile.png.mono.wav.
Usage:
node as-wav <file or folder>... [--mode mono|stereo]
or
npm run as-wav <file or folder>... -- [--mode mono|stereo]
If not supplied, it will default to mono.
The process for generating a wav header was derived from the code in node-wav package.