To open a WAV file for reading in sections.
INTEGER(7) FUNCTION OPEN_WAV_FILE_READ@(FILE,N_CHANNELS,N_SAMPLES,SAMPLE_RATE)
This routine opens a simple (uncompressed) .WAV file so that its contents can
be read with a series of calls to WAV_FILE_READ@. The number of samples and the
sample rate are returned by the function.
The return value is the handle to be passed to subsequent sound function
calls. A zero value indicates a corrupt WAV file or an unsupported WAV format.