added "0-based index" explanation to VTBuilder biotype docs
added "0-based index" explanation to VTBuilder biotype docs

seanisom/vtp,nakijun/vtp,nakijun/vtp,markraz/vtp,markraz/vtp,seanisom/vtp,nakijun/vtp,markraz/vtp,markraz/vtp,seanisom/vtp,seanisom/vtp,nakijun/vtp,nakijun/vtp,seanisom/vtp,markraz/vtp