Added icon [ci skip]
Integrated Archer.
Update readme [ci skip]
Updated to Typhoon 0.9 and Archer 0.3.1
Removed leading underscore from attribute names in tests (psr)
Removed unused UnixTime support class (gmdate/gmmktime functions can safely be used without clock/timezone ini requirements).
Implemented fromUnixTime() method on Date, DateTime and TimeOfDay (fixes #31)
Added fromNativeDateTime() to Date, DateTime and TimeOfDay (#17)
Added nativeDateTime() to TimePointInterface, Date and DateTime (fixes #17)
Changed intervals to have exclusive end point (fixes #26)
Added Duration class (#4)
Added IntervalInterface::duration() (#4)
Fixed bug in normalizer.
Added TimeSpanInterface and TimePointInterface::add/subtract() (#4)
Implemented TimePointInterface::differenceAsDuration() (fixes #4)
Updating travis config.
Updated readme [ci skip]
Update README.md
A few basic doco fixes (fixes #19) [ci skip]
Updated Calendar to use gmdate() for ISO/doomsday purposes.