bmxtranswrap: option to disable input tracks
bmxtranswrap: option to disable input tracks

Added the --disable-tracks input option which can be used to disable
tracks in the next input file that follows the option

Limecraft/ebu-bmx,stuarthicks/bmx,Limecraft/ebu-bmx,stuarthicks/bmx,stuarthicks/bmx,Limecraft/ebu-bmx,xunchangguo/BMX,xunchangguo/BMX,xunchangguo/BMX