adjusted 2htdp/universe (and world) so that it uses the cache disabling support from 2htdp/image

(the caching is not helping when drawing animations; it just allocates extra bitmaps)

collects/2htdp/private/universe-image.rkt

@@ -1,10 +1,17 @@
 #lang scheme/base
 (require (prefix-in 2: 2htdp/image)
+         (prefix-in 2-core: mrlib/image-core)
          (prefix-in 1: htdp/image)
          htdp/error)
 
 (provide image? scene? image-width image-height text 2:image?
-         check-image check-scene check-scene-result)
+         check-image check-scene check-scene-result
+         disable-cache)
+
+(define (disable-cache x)
+  (if (2:image? x)
+      (2-core:un/cache-image x #f)
+      x))
 
 (define (scene? x)
   ;; be sure to check 2:image? first so that

collects/2htdp/private/world.rkt

@@ -211,7 +211,7 @@
         (let ([s (send visible find-first-snip)]
               [c (send visible get-canvas)])
           (when s (send visible delete s))
-          (send visible insert (send pict copy) 0 0)
+          (send visible insert (disable-cache (send pict copy)) 0 0)
           (send visible lock #t)
           (send visible end-edit-sequence)
           ;; The following flush trades streaming performance (where updates