Print all created job ids at once.

This cuts job creation time roughly in half...
Try to protect against a temporarily unavailable database.
Hack around /pscratch being mentioned in the JobConfig in /cvmfs.
Zip the report xml file, too.
Select jobs to create from a dataset at random.
Rework function to re-attempt critical IO functions.
Reactivate work_queue input directories.
Start of by creating a basic payload of jobs.

Don't wait for workers to create more jobs, just do so and attract workers
from the get-go.