To help people familiar with Qsynth (I'm not, but it seems to be
one of the more polished FluidSynth front ends), use the same
presentation and terminology for the FluidSynth settings.
More to follow.
I don't really understand what these parameters do, or what the
sensible values are, so for now the sliders are limited only by
the allowed (or, in one case, "safe") values.
