Recycle plugin instances across a patch change.

[rerdavies]

Is your feature request related to a problem? Please describe.

Rebuilding pedalboards after a change causes a discontinuity in audio processing. If plugin instances were re-used, things like reverb tails would be continuous and uninterupted after a patch change, as long as the patches are structurally similar.

Describe the solution you'd like

When building pedalboards, reuse plugin instances from the previous pedalboard when IDs match. Eliminate the pop filter if structure is identical or substantially (?) similar. Re-used instances would preserve state across the patch change.

Requires the following changes:

• Recycling of matching plugins; garbage collection of plugins that don't get recycled.
• Conditional application of the pop filter when changing patches.
• Special handling of control changes when recycled plugins are activated in the audio loop.

Describe alternatives you've considered

Additional context