Bukkit

Added Anti-Spam message history (ex. the player can't send same the message same as the one of the five previous messages).

By using $time$ in Slow-mode warning message, you can now refer to the time a player must wait before sending a message.  (ex. You can only send one message in $time$ seconds!)

By using $history-length$ in Anti-Spam warning message, you can now refer to a number of messages that the current message cannot be the same. (ex. You cannot send the same message as the one of the $history-length$ previous messages!)