constructor(containers = [], options = {}) {
    /**
     * Current containers
     * @property containers
     * @type {HTMLElement[]}
     */
    this.containers = [...containers];

    /**
     * Current options
     * @property options
     * @type {Object}
     */
    this.options = {...options};

    /**
     * Current drag state
     * @property dragging
     * @type {Boolean}
     */
    this.dragging = false;

    /**
     * Current container
     * @property currentContainer
     * @type {HTMLElement}
     */
    this.currentContainer = null;

    /**
     * Draggables original source element
     * @property originalSource
     * @type {HTMLElement}
     */
    this.originalSource = null;

    /**
     * The event of the initial sensor down
     * @property startEvent
     * @type {Event}
     */
    this.startEvent = null;

    /**
     * The delay of each sensor
     * @property delay
     * @type {Object}
     */
    this.delay = calcDelay(options.delay);
  }
Sensor constructor.
@constructs Sensor
@param {HTMLElement[]|NodeList|HTMLElement} containers - Containers
@param {Object} options - Options