for e.g.:
A CCSprite ( g_all.g_ccsprite = CCSprite:create(“xxx.png”) ) has been added to a CCLayer, and CCLayer has been added to a CCScene.
If CCScene be distroyed by CCDirctor:replaceScene(). Then every CCLayer and CCSprite in this CCScene will released too.
In this condition, how can I identify if this CCSprite (g_all.g_ccsprite) is still availble? 