Clean up Body
Use space partitioning to check collisions

This is an optimization that was long overdue. Instead of using one
large space to look for collisions between Narjillos and food, I
partition the space into a grid of small areas. As long as a Narjillo
never moves fast enough to skip an area, I can search for food only in
the neighboring squares of the Narjillo. This makes the entire system
almost 30% faster.
Cut-off rendering framerate when light is off
Move hi-speed toggling to "s" key
Update backlog
Fix interaction of regular lamp and infrared

When you turn infrared on while the lamp is off, turn on the lamp.
When you turn the light off while infrared is on, turn off infrared.