The RTC module has been added thanks to https://github.com/msparks/arduino-ds1302 . I used the DS1307 over the DS1307 as it was lower cost and had all the functionality I needed, but I was surprised at the lack of support in the Arduino world. Partly because of the I have decided to stick with the software clock and have that synced with the hardware clock when inserted in to a computer. This allows any RTC module to be easily retrofitted to the design without a large anount of work.