title: cocos2d: alloc ccsprite memory 4MB, adding as child to scenes mem=11MB
body: <p>i have started with helloworld template.
  added some menu and started performance tool->allocation.
  result: 1.9MB
  ok, so the empty scene is 2MB
  now added instance variable ccsprite initialized with an image 1024x1024</p>
  
  <pre><code>CCsprite *test=[CCSprite spriteWithFile:@"img1024x1024.png];
  </code></pre>
  
  <p>and started performance tool->allocation.
  result: 6MB
  ok, the image in memory is 4MB, +2MB of the empty
  now added to the schen with </p>
  
  <pre><code>[self addChild:test];
  </code></pre>
  
  <p>performance tool->allocation.
  result: 11MB
  is that normal?
  every sprite i'll add as child will double my memory usage?
  thanks </p>