[AndyB] Weekly newsletter Xenforo 2.4

Weekly newsletter v2.4 changes:

• Cron entry now triggers a XenForo Job.

Weekly newsletter v2.1 changes:

• Added forum view permissions.

Weekly newsletter v1.8 changes:

Added the ability to add an announcement.

Weekly newsletter v1.7 changes:

Added "stats" function to show how many emails will be sent.

Q: How can I determine the number of emails that will be sent?
A: Add weeklynewsletter/stats to your forum URL.