Changes to the changes to the ChatAPI.

mcMMO will not pass null for any events that it creates about itself.
Older plugins which are using depricated methods in ChatAPI will be null.
Newer plugins passing null to ChatAPI will also be null.

Null guarantees that it is not from mcMMO, but from an external plugin that is not specified.

src/main/java/com/gmail/nossr50/events/chat/McMMOPartyChatEvent.java

@@ -13,10 +13,6 @@ public class McMMOPartyChatEvent extends McMMOChatEvent {
         this.party = party;
     }
 
-    public McMMOPartyChatEvent(String sender, String party, String message) {
-        this(null, sender, party, message);
-    }
-
     /**
      * @return String name of the party the message will be sent to
      */