Ports can only have a single input or output, so no need for two counters.
And keeping track of the connected node means we can check for
INPLACE_BROKEN plugins, if multiple ports connect to the same node.
Removes the need for VLAs before ladspa call in rvoice mixer and number
for for loops to set up and advance the buffers. Also reduces the number
of state changes (and atomic operations) by calling fluid_ladspa_run only
once.
Knowledge of FluidSynth is completely removed from the LADSPA effects
unit. All synchronization happens inside LADSPA with atomic operations.
The LADSPA fx instance created by FluidSynth is only special in that
FluidSynth knows about it and calls it's run method when enabled.
This simplifies the code structure, makes the FluidSynth and the LADSPA
engine easier to maintain due to the loose coupling. It also enables
users to create their own (or additional) LADSPA fx unit for further
processing as soon as we expose the LADSPA functions via a public API.
