* GetNextScheduledEpochNoCatchup implementation
* Add tests for cron schedule nocatchup
* Add tests for periodic schedule and fix a corner case
* Integrate no catchup behavior in swf controller
* Update job api proto
* Regenerate backend client
* Pass catchup parameter in backend api
* Rename proto field to no_catchup, so that it has backward compatible default value
* Update generated backend api
* Use no_catchup field instead
* Add some comments