[2.1.5] Fixing critical bugs those were resolved at v3.0.

1) [JSB] Iterating through cc.Node children causes crash. Issue URL is http://www.cocos2d-x.org/issues/2315
2) EditBox doesn't show any text in TestJavascript/ExtensionsTest/EditBoxTest. Issue URL is http://www.cocos2d-x.org/issues/2337