Update WorldEditCUIMessage for Message being an interface

src/main/java/com/sk89q/worldedit/spout/WorldEditCUIMessage.java

@@ -24,7 +24,7 @@ import org.apache.commons.lang3.builder.ToStringBuilder;
 import org.spout.api.protocol.Message;
 import org.spout.api.util.SpoutToStringStyle;
 
-public class WorldEditCUIMessage extends Message {
+public class WorldEditCUIMessage implements  Message {
     private final String message;
 
     public WorldEditCUIMessage(String mesage) {