cd_play (var from, var to);
Plays audio tracks off a CD.
||the start track (1..99),which immediately begins playing
after the instruction.
||the end track (1..99) until which the CD is to be played.
If to has a higher value than the number of tracks
on the CD, the CD will be played to its end.
The number of audio tracks on the CD if the instruction was
successful, otherwise 0.
cd_play(1,99); // play the whole cd
cd_start, cd_pause, cd_track,