> corrected note saying that the header was 500 bytes long (512 bytes are written and the number 512 is given elsewhere)
> altered confusing language about how long the chunks are ("length of chunk" implies the number includes the chunk-header. chunk-data-length less so, and reflects the fact that the number written doesn't include the chunk-header)
> removed mistake about how texture coordinates are encoded (the last release, and the current head both write texture coordinates as 3 float components regardless of what they actually are)