alsa:
- support for sub-devices;
- fixed 24-bit format support for some devices which on little-endian machine operate only in big-endian format, example of such device is Audio4DJ which supports only SND_PCM_FORMAT_S24_3BE (for this patch implemented support only for 24-bit audio samples although other formats may be added in case of necessity and if such devices exist);
! special thanks to Owen Williams from Mixxx project who tested these changes/fixes on real Audio4DJ device.