* @param {Date|Number} date - the date to be changed
* @param {Number} amount - the amount of milliseconds to be added. Positive decimals will be rounded using `Math.floor`, decimals less than zero will be rounded using `Math.ceil`.
* @returns {Date} the new date with the milliseconds added
* @throws {TypeError} 2 arguments required
*
* @example
* // Add 750 milliseconds to 10 July 2014 12:45:30.000: