Corrected the bytes per second computation and got rid of the extra form...

Hi Andrew,
I noticed that the playback of the wav files generated from the wav package caused the progress bar of the player to move incorrectly. I found two reasons
1. The bytes per second was not computed correctly
2. The extra format bytes were not applicable in case of uncompressed PCM

Btw .. thanks a lot for writing up such a package.
Regards,
Kashyap