Yay! Simulation and rendering are now running in separate threads.
Speedup is significant, now ~600 gens/s up from ~450 gens/s in single thread.
Fixed randomization of world by pressing spacebar.
Input thread just tells simulation thread we need a new random world, rather than doing it itself.
Awesome! Original functionality is back, with +33% simulation speed!
Next up, clean up this code... not terribly ugly, but could be more concise.