Replacement guide javadocs for deprecated classes

Fixes vaadin#8682

Author: Ilia Motornyi

compatibility-server/src/main/java/com/vaadin/v7/data/Buffered.java

@@ -18,6 +18,7 @@
 
 import java.io.Serializable;
 
+import com.vaadin.data.Binder;
 import com.vaadin.server.AbstractErrorMessage;
 import com.vaadin.server.ErrorMessage;
 import com.vaadin.server.ErrorMessage.ErrorLevel;
@@ -45,6 +46,8 @@
  *
  * @author Vaadin Ltd.
  * @since 3.0
+ * @deprecated As of 8.0, no replacement available, see {@link Binder#writeBean(Object)}, {@link Binder#clearFields()}
+ *
  */
 @Deprecated
 public interface Buffered extends Serializable {

compatibility-server/src/main/java/com/vaadin/v7/data/BufferedValidatable.java

@@ -16,6 +16,8 @@
 
 package com.vaadin.v7.data;
 
+import com.vaadin.data.Binder;
+
 import java.io.Serializable;
 
 /**
@@ -27,6 +29,7 @@
  *
  * @author Vaadin Ltd.
  * @since 3.0
+ * @deprecated As of 8.0, no direct replacement available. See {@link Binder}, {@link com.vaadin.data.Validator}.
  */
 @Deprecated
 public interface BufferedValidatable