tentatively refactor quad tree to make it more succinct + eliminate a class of potential bugs (passing wrong quad values through recursion)

fcore/player.sml

@@ -320,6 +320,9 @@ struct
     let
       val player = #player game
 
+      val _ = print ("(playerX, playerY) = (" ^Int.toString (#x player) ^ ", " ^
+      Int.toString (#y player) ^ ")\n")
+
       val patches = getProjectilePatches player
       val player = PlayerPatch.withPatches (player, patches)
 
@@ -427,8 +430,8 @@ struct
 
       val ww = Constants.worldWidth
       val wh = Constants.worldHeight
-      val enemyCollisions = QuadTree.getCollisions
-        (x, y, size, size, 0, 0, ww, wh, 0, enemyTree)
+      val enemyCollisions = QuadHelp.getCollisions
+        (x, y, size, size, enemyTree)
     in
       Vector.fromList enemyCollisions
     end