DragonBones龙骨插槽的隐藏

参考：

插槽中对象的显示与隐藏问题

let factory = dragonBones.EgretFactory.factory;
factory.parseDragonBonesData(RES.getRes("test_ske_dbbin"));
factory.parseTextureAtlasData(RES.getRes("test_tex_json"), RES.getRes( "test_tex_png"));
let armatureDisplay = factory.buildArmatureDisplay(name);
this.addChild(this.armatureDisplay);

//隐藏插槽
armatureDisplay.armature.getSlot("Sprite").displayIndex = -1;
//显示插槽
armatureDisplay.armature.getSlot("Sprite").displayIndex = 0;