Remove unused string buffer

03/main.pony

@@ -151,7 +151,6 @@ class Grid
       max_x = p.x().max(max_x)
       max_y = p.y().max(max_y)
     end
-    var buf = recover String((((max_x - min_x) + 1) * (max_y - min_y)).usize()) end
     for y in Range[I64](min_y, max_y + 1) do
       for x in Range[I64](min_x, max_x + 1) do
         if (y == 0) and (x == 0) then