I added code to support the alarm functionality in the DS1337 (and theoretically the DS3231 found in the ChronoDot).

By creating an instance of RTC_DS1337 instead of RTC_DS1307, you can use the alarm functionality. This includes two alarms, one with to-the-second resolution and one with to-the-minute resolution. My code lets you set the alarms, disable them, and check or clear the flags on the chip.