Added missing duration unit short names that are supported in scala.concurrent.duration.DurationConversions.
Added more duration unit short names for hour, minute and second.
Revert "Added more duration unit short names for hour, minute and second."

This reverts commit ebb526304ecebb561ba5c5f4ff4ce369b303e6e0.
Patch spec with duration units from Scala that were previously missing.
Merge pull request #184 from alexwei/master

Added missing duration unit short names that are supported in scala and more