Attempt to fix some space leaks, general cleanup

src/Dodge/Wall/Delete.hs

@@ -3,6 +3,7 @@ module Dodge.Wall.Delete (
     deleteWallID,
 ) where
 
+import Data.Foldable
 import Control.Lens
 import qualified Data.IntSet as IS
 import Dodge.Data.World
@@ -24,4 +25,4 @@ deleteWall wl =
     i = _wlID wl
 
 deleteWallIDs :: IS.IntSet -> World -> World
-deleteWallIDs is w = foldr deleteWall w $ IM.restrictKeys (_walls (_cWorld w)) is
+deleteWallIDs is w = foldl' (flip deleteWall) w $ IM.restrictKeys (_walls (_cWorld w)) is