DS1307 Real-time Clock Library

As committed in my last post, I’ve put up my next coding effort on GitHub.
Get code here: https://github.com/prawnhead/DS1307
The DS1307 is a highly accurate clock module that connects to the Arduino via the I2C protocol (SDA/SCL lines). As implemented on the Sparkfun BOB-00099 break-out board it comes complete with a crystal (to keep time) and a watch battery so that it maintains current time even when not being powered externally.
This library was developed to be a full-featured implementation of the DS1307 chip. This includes the cool but probably not very often used feature of having 56 bytes of NVRAM that is persistent and can be read/written very simply.
I’m torn between a simple-as-pie implementation and the one I know I really need. At this stage I’ve only covered the simple option; you need to read/write the date/time as a set of bytes. I’d rather have the class read and write a DateTime data type, but I think that’s too much for people who want the basics. (Correct me!) I have a DateTime class that I’ve created, tested and used but that I haven’t posted on GitHub yet. That’s next.
I honestly don’t know how collaboration is achieved on GitHub yet. I understand at this stage that anyone can clone my repo and go to town on my code. That’s what I want, that’s great. But I also want people to suggest improvements and commit them!I’m unsure of how this happens. Is it anything goes? Is it “commits only by repo members?” Is there an approvals process? I need to go an answer these questions. For now, here’s the simple version of this class. I guess the appropriate thing to do is to fork it and build on the ‘advanced’ version of the same. Again, questions. If the same repo now makes two versions available, how are they surfaced? I guess I’ll go ahead and see.
That is all.