Merge branch 'release/0.1.1' into develop
Added missing support for timezones to Date::fromUnixTime(), fromNativeDateTime() and nativeDateTime().
Added support for raw integer seconds to TimePointInterface::add() and subtract() (fixes #35)
Implemented TimePointInterface::differenceAsSeconds() (fixes #36)
Implemented comparison methods on: Date, DateTime, Duration, TimeOfDay,
TimeZone, Interval. (Fixes #34)
Added missing use statements.
Moved differenceAsSeconds() into AbstractTimePoint class.
Merge pull request #38 from koden-km/feature/comparison-methods

Implemented comparison methods (Fixes #34)
Moved Duration and TimeSpan interface into TimeSpan namespace, removed unnecessary AbstractDuration and DurationInterface.
Added createFromDate() static methods to Year/Month interval classes.
(Fixes #37)
Changed createFromDate() to createFromTimePoint() as suggested. (Fixes
Merge pull request #39 from koden-km/feature/easy-create-interval

Added createFromDate() static methods to Year/Month interval classes.
Expanded TimeSpanInterface considerably, reimplemented Date[Time]::add/subtract() in terms of TimeSpan (#32).
Completed period implementation (#32)
Updated typhoon checks.
Merge branch 'feature/period' into develop
Updated links in README.md [ci skip] (fixes #41).
Updated changelog.
Added TimeSpanInterface::string/__toString(), and AbstractTimePoint::differenceAsPeriod() (fixes #48, #47).
Renamed createFromXXX to fromXXX (fixes #46)