Load default soundfont if midi files specified but no soundfont
Load default soundfont if midi files specified but no soundfont

It makes little sense to play midi files without a soundfont, so
try to load the default one in that use case.

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