The check for igniters (fire/lava) will be performed every 10 secs
if the item is flammable.
if the item is found to be in lava it will then burn up and
disappear in a smoke puff.
If a non-lava igniter node is found, a combination of `flammable`
value of the item and `igniter` group value of the node will be used
to determine the chance for the item to be removed.
Each sapling is given a single node timer that is between
2 and 4 days of game play time (40-80 minutes). If you walk out
of the zone, and come back later, the tree will always grow
to full if the timer has elapsed.
Because trees.lua is all functions, it needs to be parsed before
nodes.lua, since that references some of its functions. Hence,
change the order of parsing here. Otherwise saplings would not
grow to full.
* Move furnace related code into furnace.lua
* Move duplicated code into functions
* Rewrite ABM:
* Easier to follow strcuture (no returns in the middle)
* No unnecessary calls to get_craft_result
* Split logic and "visual feedback" (a bit)
* Fewer calls to meta:set and meta:get
* Better feedback on the current state of the furnace
