Fix javadoc

Change-Id: Ifda7b33b21ebe5bccb34559d9dc7617a7898a39a

server/src/com/vaadin/server/Constants.java

@@ -19,9 +19,9 @@ import com.vaadin.shared.communication.PushMode;
 import com.vaadin.ui.declarative.DesignContext;
 
 /**
- * TODO Document me!
+ * Internal constants used by both the client and the server side framework
  * 
- * @author peholmst
+ * @since 6.2
  * 
  */
 public interface Constants {