.lispwords @ 93040e2c402e

Episode 17: Particles Optimization

I decided not to follow this video, and still keep using vectors in the
particles because it's good practice for me.  Instead I took the time to turn
`particle` into a struct to save some cycles (the `(disassemble 'particle-*)`
functions look a lot nicer now) and made `zap%`.

(1 scancode-case)
(1 make-sketch)
(2 with-vals)