Allow players to monitor joins and leaves of their faction members.

Larger servers tend to have join and leave messages disabled for the entire server. A few have requested to allow faction members to monitor join and leave messages of their own members.

src/main/java/com/massivecraft/factions/FPlayer.java

@@ -32,6 +32,10 @@ public interface FPlayer extends EconomyParticipator {
 
     public void setFaction(Faction faction);
 
+    public void setMonitorJoins(boolean monitor);
+
+    public boolean isMonitoringJoins();
+
     public Role getRole();
 
     public void setRole(Role role);