This automatically creates the correct collection of name label, value
label and "editor" (knob, checkbox, dropdown) depending on the processor
type and layouts them vertically.
If the underlying parameter is logarithmic, the slider respects that and
switches to a logarithmic display. Currently, the used base is e, and
we'll have to see in practice if 2 or 10 might be better. The parameters
that make use of this, as can be seen in the previous commit, are all of
the time dependent parameters such as the synth envelope parameters, as
with these, usually fine-grained control at small time scales and
coarser control at large time scales is desired.
This was a good opportunity to refactor the slider step count into a
constant.
