Refactor, add bullet modules and weapon effect modifiers

src/Dodge/Item/Weapon/Shell.hs

@@ -0,0 +1,27 @@
+module Dodge.Item.Weapon.Shell
+    where
+import Dodge.Data
+import Geometry.Vector
+
+import Control.Lens
+decTimMvVel :: Projectile -> World -> World
+decTimMvVel pj = projectiles . ix pjid %~
+    ( (pjTimer -~ 1) 
+    . (pjPos   %~ (+.+ vel) )
+    . (pjAcc   %~ rotateV rot )
+    )
+  where
+    rot = _pjSpin pj
+    vel = _pjVel pj
+    pjid = _pjID pj
+
+--pjAutoSpin :: Projectile -> World -> World
+--pjAutoSpin pj = projectiles . ix pjid %~
+--    ( (pjDir -~ 1) 
+--    . (pjPos   %~ (+.+ vel) )
+--    . (pjAcc   %~ rotateV rot )
+--    )
+--  where
+--    rot = _pjSpin pj
+--    vel = _pjVel pj
+--    pjid = _pjID pj