Event delegate for scheduled jobs

[mattesmohr]

At the moment the event delegate only works for regular jobs. You can work around it, but I think it would be nice to have it "in-build".

We could possibly add the notification hook to the method, where the job is about to run. I think its in ScheduledJob on line 49.

But also I think we need to define a different event delegate for a schedule job as well.