Added native PHP DateInterval methods to Period/Duration (fixes #57)
Added Period/Duration fromNativeDateInterval() (fixes #61, refs #57)
Added Kev to composer authors.
TimeSpan::resolveToInterval() methods now correctly handle negative spans (fixes #58)
Merge pull request #61 from koden-km/feature/native-dateinterval

Added native PHP DateInterval methods to Period/Duration (fixes #57)