Adding support for BCD/binary conversion of vector data.
Adding initial support for time/date structure (common for DS1307/DS3231).
Improving DS1307 device driver; using common time/date structure.

1. Adding control bit field structure.
2. Using common time/date structure.
3. Updating example sketch.
Adding support for DS3231 Extremely Accurate I2C RTC/TCXO/Crystal.