Add listener to persist relationship between job and task

This introduces a listener that stores the association between a Spring
Batch job and the task it was executed within.

Resolves spring-cloud/spring-cloud-task#46

Merge Changes based on code review.

spring-cloud-task-samples/timestamp/README.adoc

@@ -1,4 +1,4 @@
-= Timestamp Job
+= Timestamp Task
 
 This is a Spring Cloud Task application that logs a timestamp.
 

spring-cloud-task-samples/timestamp/pom.xml

@@ -15,7 +15,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>1.3.2.RELEASE</version>
+		<version>1.3.3.RELEASE</version>
 	</parent>
 
 	<properties>

spring-cloud-task-samples/timestamp/src/main/java/org/springframework/cloud/task/timestamp/TaskApplication.java

@@ -40,6 +40,8 @@ import org.springframework.context.annotation.Bean;
 @EnableConfigurationProperties({ TimestampTaskProperties.class })
 public class TaskApplication {
 
+	private static final Log logger = LogFactory.getLog(TaskApplication.class);
+
 	@Bean
 	public TimestampTask timeStampTask() {
 		return new TimestampTask();
@@ -53,7 +55,6 @@ public class TaskApplication {
 	 * A commandline runner that prints a timestamp.
 	 */
 	public class TimestampTask implements CommandLineRunner {
-		private final Log logger = LogFactory.getLog(TimestampTask.class);
 
 		@Autowired
 		private TimestampTaskProperties config;