Various fix and improvements

What's Changed

• Add slam region to Distressor drive stage for enhanced distortion by @fedemone in #73
• Add rhythmic add-ons, filter self-oscillation, and LFO envelope shapes by @fedemone in #72
• OmniPress, NeonLabirinto, LuceAlNeon, PortaCassette: drumlogue dropout fixes, Multiband on Standard's curve, measured build levels by @fedemone in #74

Full Changelog: 3.0...3.2