Method onWindowBlur

src/controller/Controller.js:64–72

* Called on window blur, sets button state to up if button was down; * @return {void}@memberof Controller

()

   * @return {void}@memberof Controller
   */
  onWindowBlur() {
    for (const key of Object.keys(this.buttons)) {
      const button = this.buttons[key];

      if (button._state === 1) {
        this.buttons[key].updateState(2);
      }
    }
  }

  /**
   * Sets an object of button functions to the controller to be called.