Add laser central room, using new placement/roompos functionality

src/Dodge/PlacementSpot.hs

@@ -7,27 +7,30 @@ import System.Random
 
 -- TODO rename to any unused link facing out
 anyLnkOutPS :: PlacementSpot
-anyLnkOutPS = PSLnk f (const id) Nothing
+anyLnkOutPS = PSPos f (const id) Nothing
   where
-    f (UnusedLink p a) = Just $ PS p a
+    f (UnusedLink p a) = Just (PS p a, PosPl p a)
     f _ = Nothing
     
 fstLnkOut :: PlacementSpot
-fstLnkOut = PSLnk f (const id) Nothing
+fstLnkOut = PSPos f (const id) Nothing
   where
-    f (OutLink 0 p a) = Just $ PS p a
+    f (OutLink 0 p a) = Just (PS p a, PosPl p a)
     f _ = Nothing
 
 anyLnkInPS :: Float -- ^ amount to shift inward
     -> PlacementSpot
-anyLnkInPS x = PSLnk f (const id) Nothing
+anyLnkInPS x = PSPos f (const id) Nothing
   where
-    f (UnusedLink v a) = Just $ PS (v -.- x *.* unitVectorAtAngle (a + 0.5 * pi)) (a+ pi)
+    f (UnusedLink v a) = Just (PS v' a' ,PosPl v' a')
+      where
+        v' = v -.- x *.* unitVectorAtAngle (a + 0.5 * pi)
+        a' = a + pi
     f _ = Nothing
 
-useLnkRoomPos :: RoomPos -> Maybe PlacementSpot
+useLnkRoomPos :: RoomPos -> Maybe (PlacementSpot,RoomPos)
 useLnkRoomPos rp = case rp of
-    (UnusedLink (V2 x y) a) -> Just $ PS (V2 x y) a
+    (UnusedLink (V2 x y) a) -> Just (PS (V2 x y) a , PosPl (V2 x y) a)
     _ -> Nothing
 
 psRandRanges :: (Float,Float) -> (Float,Float) -> (Float,Float) -> State StdGen (Point2,Float)