你好：
关于龙骨换肤的问题，可以参考下我们的APISkeleton
replaceSlotSkinByIndex(slotName:String, oldIndex:int, newIndex:int):void
替换插槽的贴图索引
replaceSlotSkinName(slotName:String, oldName:String, newName:String):void
替换插槽贴图名
setSlotSkin(slotName:String, texture:Texture):void
设置自定义皮肤
