* - trigger new "cron" event
- check cron string syntax
- added croniter to requirements
* - run scheduler ever 60 sec
- trigger all enabled events
- enqueue if now >= next time execution since last one
* Update task-runner.md
* fixed tests
* fix triggering with now = True
* modified sobstitution to cron_map
modified annually label to annual
* ability to use labels defined in cron_map in cron string definition
299ab6198a