Spam control: Add ability to return IP address of $uid

A new permission: 'View IP Address' will allow the logged-in user to view the IP address of a given $uid.

Use Case:
Administrator of a forum needs to see the IP address of the poster of a topic or comment. Often spammers will post as two different users: the spammer will post a problem as User A, then a few days later they will answer the question as User B.

See this thread: http://www.webmaster-forums.net/showthread.php?t=39910