* Adds defines for world.tick_usage
* This provides no useful benefit whatsoever, but /tg and Baystation12 have done it, so it will make porting future code easier if we do too. No real harm done either.
New lighting system is needed to handle updating literally 14k+ tiles whenever the sun moves. The straight port seems to have had no adverse effects from what I could see. Don't know if it's more performant but it doesn't seem to be less.
I didn't expect the latter would be needed for the former.
