added support for cancel while writing a BT file
added support for cancel while writing a BT file

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