Added repeated when to When object
Added datetime_iterator for specification
Return inner duration/period on repeated-when
Removed a when-check from runcaps (already checked in model)
MultiJob for Scheduler
Fixed a bug in Envelop and added len() function
Finalized repeated when in model
Merge pull request #18 from MKV21/subspec-schedule

MultiJob and repeated-when from D1.4, fixes #6