New API functions, new group actions

 4 new API functions have been added to FastCron:

• cron_batch_add to add multiple cronjobs at once.
• cron_batch_edit to update multiple cronjobs at once.
• cron_batch_delete to delete multiple cronjobs at once.
• cron_group_edit to update multiple cronjobs in a group at once.

The new function documentation can be found here: https://www.fastcron.com/documentation/api/cron#batch-add-action

It's now recommended to use the API function in the format target_action e.g. cron_add instead of the old format cron.add. However, the old format will be maintained indefinitely for legacy uses.

3 new group actions have been added:

• Edit cronjobs: to edit all cronjobs in a group at once
• Delete cronjobs: delete all cronjobs in a group
• Delete group & cronjobs: delete a group and its cronjobs.