Moderator notifications (aka Mod Notify)

Private message can be sent at such events:
- open thread
- close thread
- sticky thread
- unsticky thread
- approve post
- unapprove post
- approve thread
- unapprove thread
- merge threads
- move thread
- copy thread
- redirect thread
- split thread
- change thread subject
- delete post
- delete poll
- delete post

Plugin automatically adds the task performed in the background - notifications are queued and sent from up to 5 minute delay.