Reorganise geometry modules slightly

src/Geometry/ConvexPoly.hs

@@ -5,7 +5,7 @@ module Geometry.ConvexPoly
     , cpPoints
     , cpCen
     , cpRad
-    , centroid
+--    , centroid
     , pointsToPoly
     , convexPolysOverlap
     , pointInPolyPoints
@@ -14,9 +14,10 @@ import Geometry.Data
 import Geometry.Vector
 import Geometry.LHS
 import Geometry.Intersect
+import Geometry.Polygon
 
 import Control.Lens
-import qualified Control.Foldl as L
+--import qualified Control.Foldl as L
 data ConvexPoly = ConvexPoly
     { _cpPoints :: [Point2]
     , _cpCen    :: Point2
@@ -68,7 +69,5 @@ pairPolyPointsIntersect a' b' (c':d':xs') = go c' a' b' (c':d':xs')
     go _ _ _ _ = False
 pairPolyPointsIntersect _ _ _ = False
 
-centroid :: Foldable t => t Point2 -> Point2
-centroid = L.fold $ (/) <$> L.Fold (+.+) (V2 0 0) id <*> L.genericLength
 
 makeLenses ''ConvexPoly