Add Job Event Messaging to tasks.

* Added test for sample and cleanup

* Added skipEventsListener

* Added new message format.

* Added integration tests.

* Updated application.properties to add json content type

resolves spring-cloud/spring-cloud-task#119

spring-cloud-task-integration-tests/pom.xml

@@ -36,5 +36,10 @@
 			<version>1.0.0.BUILD-SNAPSHOT</version>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.cloud</groupId>
+			<artifactId>spring-cloud-task-batch</artifactId>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 </project>