#103 sound corruption with full duplex

[Diemo Schwarz]

When using the inputs as well as the outputs with the
alsa driver,
occasionally when heavier interaction takes place
(opening a patch or an editor window, loading a sound
file), jmax "loses sync", i.e. the output sound is
corrupted by heavy artefact noise, until the buffer
size is changed.

This was observed so far with jmax 4.0.x and 4.1 with
the Hammerfall HDSP PCMCIA and PCI, as well as an ac97
internal Laptop soundcard, with alsa 0.94 and 1.x.