removeNodes(nodes, duration) {
    if (nodes) {
      if (_.isArray(nodes)) {
        for (let i = 0, il = nodes.length; i < il; i++) {
          this.removeNode(nodes[i], duration);
        }
      } else {
        this.removeNode(nodes, duration);
      }
    }
  }
Removes nodes/sprites (note: does not create them, use NodeFactory to handle that!).
@param {Object|Array} nodes a single or array of nodes/sprites
@param {Object} [duration=0.0] duration of remove