[stromb0li] Happy Birthday Emails 1.0.2

This allows for automated emails of happy birthday messages to your community.

Features:
Customize both the subject and body of the email sent (body of the message may contain html)
Leverage user attributes in both the subject and body of the message along with the board title.
Test messages prior to running in production by specifying named users that will always receive an email, regardless of settings.

Filter who receives birthdays based on:

1. Target user group (user must be a part of one of the selected groups, either as primary or secondary group)
2. Banned status
3. Minimum message count

How this works:

• A new checkbox is added to the user's account details, allowing opt in or out of happy birthday emails.
• If opted in (which is by default), an email is sent if their account fits the filters defined.
• Messages are scheduled for sending as part of a cron job called "Happy Birthday: Daily emails" that runs daily at 10AM. You can adjust the cron schedule if you prefer a different time.