First (buggy) implementation of rewind gun

src/Dodge/Data.hs

@@ -115,6 +115,7 @@ data World = World
     , _config               :: Configuration
     , _preloadData          :: PreloadData
     , _savedWorlds          :: M.Map SaveSlot World
+    , _rewindWorlds         :: [World]
     , _frameClock           :: Int
     }
 
@@ -421,12 +422,17 @@ data ItemDimension = ItemDimension
 
 data ReloadType = ActiveReload | PassiveReload SoundID
 
+-- I believe this is called every frame, not sure when though
 data ItEffect = NoItEffect
     | ItInvEffect 
         {_itInvEffect       :: ItEffect -> Creature -> Int -> World -> World
                 -- the Int is the items inventory position
         ,_itEffectCounter   :: Int
         }
+    | ItRewindEffect
+        {_itInvEffect       :: ItEffect -> Creature -> Int -> World -> World
+        ,_itStoredWorlds    :: [World]
+        }
     | ItEffect 
         {_itInvEffect       :: ItEffect -> Creature -> Int -> World -> World 
         ,_itFloorEffect     :: Int -> World -> World