Needs to be done
================

- clean up all '!FIX!'es and '-FIX-'es

- render: implement ramping of modulators (volume, pitch bend, mod
    wheel, pressure, ...)

- render: fix resonance limiting so it doesn't blork at zero with
    high cutoffs

- all: make modwheel->cutoff and pressure->resonance modulations
    configurable

? GUI: should Patch Edit Save Changes select the program number of
    the saved-to patch?

? GUI: add patch import (just set values, select Patch Edit tab)