Some QoL changes and some fixes

you can now add comments before the function

trees neighbour condition no longer wraps around the field because that was somewhat unintuitive and confusing

you can now iterate Items, Entities, Ground, Unlocks with a for loop

the camera can now also be moved with WASD

get_world_size, get_water, use_item, trade, move and till now also remain unlocked after the reset. They are useless until you've unlocked the items/entities needed but you don't get an error for trying to use them before.

fixed first piggy being ignored

fixed drone position not reset on reset()

fixed trading non integral quantities

fixed operator associativity