* deal with sio_{read,write} possibly moving less data than requested
* check for out-of-sync conditions and restart if they occur
makes running jackd over aucat much more reliable
- add sndio backend
playback under aucat server is pretty solid. for full-duplex,
starting aucat with 'aucat -l -b 2048' and jackd with just
'jackd -d sndio' seems to work best for me. we want low latency
anyway, right ;)