Collection>>noDifference: can be implemented more efficiently
Collection>>noDifference: can be implemented more efficiently

Using #symettricDifference: is elegant, but it is sufficient to compare
the size of the collections and if the same compare the size of the
intersection to see if it is also the same.

jgfoster/Dolphin,blairmcg/Dolphin,shoshanatech/Dolphin,dolphinsmalltalk/Dolphin,objectarts/Dolphin,jgfoster/Dolphin,jgfoster/Dolphin,dolphinsmalltalk/Dolphin,blairmcg/Dolphin,dolphinsmalltalk/Dolphin,blairmcg/Dolphin,jgfoster/Dolphin,shoshanatech/Dolphin,shoshanatech/Dolphin,blairmcg/Dolphin,shoshanatech/Dolphin,dolphinsmalltalk/Dolphin,objectarts/Dolphin