File clean up

Remove unnecessary zone identifier files.

Bug fix, report cron errors.

Fix issue failing to run a new command without a last run time. Trap errors with invalid cron expressions.

Command history

Added the command history entity and view.

Command history

Added the command history entity and view.

Symfony 4.4

Bug fixes.
Implement proper idle-time processing based on command option.
Add delete-old-jobs-after command option for control of removal of old single-run jobs.

Symfony 4.4

Release targeting Symfony version 4.4

Symfony 3.4

Bug fixes.
Implement proper idle-time processing based on command option.
Add delete-old-jobs-after command option for control of removal of old single-run jobs.

Symfony 3.4

Release targeting Symfony version 3.4