Serial command getDiscType() may cause issues with CD capable players.

[dude22072]

On players with a CD tray, if the ?D command is sent while a CD/CDV/VSD is inserted it will return the error E04, however the PlayerCommunication::getDiscType() is simply checking if the second byte is 0/1, meaning that the capture app will incorrectly think a CAV Laserdisc is inserted. Furthermore these players have a separate ?K status command, where the 4th byte will be 0 for a CD or 1 for a CDV (and presumably VSD as well). Complementary to ?D this ?K command will return E04 if a laserdisc is inserted.