Update all Processing sketches to use the OPC.pde version from
grid24x8z_clouds that uses background/async socket management, and
doesn't grid to a halt every time the server drops out

that repeats a sequence over an LED string.

When using multiple OPC connections, prevents disconnected server(s)
from stalling the client.

struct import missing

- Remove MIDI inputs that only make sense on the Q49 keyboard
- Expire particles with zero intensity, and cap the max particles
- Lower particle generation rate

I wrote this before FC had gamma correction, I think?

This changes the doFrame() API!

Helps with testing effects in fast/slow motion