Version:
	1.0	 4 Oct 2010  -  initial release
	1.1	26 Jan 2012  -  added support for Arduino 1.0 IDE
	2.0	13 Feb 2016  -  added begin()
				added getUnixTime()
				added support for Arduino Due, Arduino Leonardo, Bobuino and chipKit
				added support for hardware I2C (all platforms)
				modified setDOW() to calculate DOW from RTC date if desired
				fixed a bug that made the library freeze when using D0 for SDA
				fixed a bug in getMonthStr() and getDOWStr()
