address remaining vertical duplicate issue (I was returning 1 from getTopmostY's loop, when I was meant to be returning 0)

fcore/quad-tree.sml

@@ -348,9 +348,7 @@ struct
 
   local
     fun loop (x, y, ex, ey, grid) =
-      if y = 0 then
-        1
-      else if ey <= 0 then
+      if y = 0 orelse ey = 0 then
         0
       else if quadHasSameColour (x, y, ex, ey, grid) then
         loop (x, y - 1, ex, y, grid)
@@ -492,6 +490,10 @@ struct
       val length = List.length list
       val _ = print ("length = " ^ Int.toString length ^ "\n")
 
+      val _ = print "start fold\n"
+      val _ = List.foldl (fn (item, _) => printItem item) () list
+      val _ = print "finish fold\n"
+
       val f = folder
         ( windowWidth
         , windowHeight