#104 output channel switching

[Diemo Schwarz]

It can happen that the second audio output channel
switches to 0 by itself, usually creating a signal
twice as loud and thus distorted. The configuration
editor still shows "1", and you have to change to
something else and then to 1 again to set it back.

This happens sometimes in jmax 4.0.x and 4.1 when
changing the audio input configuration.