Added serializable to form model classes (flowable#490)

Author: ruzkant

modules/flowable-form-model/src/main/java/org/flowable/form/model/FormOutcome.java

@@ -12,10 +12,14 @@
  */
 package org.flowable.form.model;
 
+import java.io.Serializable;
+
 /**
  * @author jbarrez
  */
-public class FormOutcome {
+public class FormOutcome implements Serializable {
+
+	private static final long serialVersionUID = 1L;
 
     protected String id;
     protected String name;

modules/flowable-form-model/src/main/java/org/flowable/form/model/LayoutDefinition.java

@@ -12,10 +12,14 @@
  */
 package org.flowable.form.model;
 
+import java.io.Serializable;
+
 /**
  * @author Tijs Rademakers
  */
-public class LayoutDefinition {
+public class LayoutDefinition implements Serializable {
+
+	private static final long serialVersionUID = 1L;
 
     protected Integer row;
 

modules/flowable-form-model/src/main/java/org/flowable/form/model/Option.java

@@ -12,10 +12,14 @@
  */
 package org.flowable.form.model;
 
+import java.io.Serializable;
+
 /**
  * @author Tijs Rademakers
  */
-public class Option {
+public class Option implements Serializable {
+
+    private static final long serialVersionUID = 1L;
 
     protected String id;
     protected String name;