function shouldBailOut(x) {
      if (typeof x !== 'object'
            || x.behavior === undefined
            || x.behavior === 'auto'
            || x.behavior === 'instant') {
        // first arg not an object, or behavior is auto, instant or undefined
        return true;
      }

      if (typeof x === 'object'
            && x.behavior === 'smooth') {
        // first argument is an object and behavior is smooth
        return false;
      }

      // throw error when behavior is not supported
      throw new TypeError('behavior not valid');
    }
indicates if a smooth behavior should be applied
@method shouldBailOut
@param {Number|Object} x
@returns {Boolean}