fix inverse logic of audio.jack.multi
fix inverse logic of audio.jack.multi

addressing #135

FluidSynth/fluidsynth,FluidSynth/fluidsynth,nezticle/fluidsynth,FluidSynth/fluidsynth,nezticle/fluidsynth,nezticle/fluidsynth,FluidSynth/fluidsynth,nezticle/fluidsynth