Update Task to BOOT 2.1.M1

Migrating to use ApplicationContextRunner or ImportAutoConfiguration with SpringApp.run, instead of SpringApplicationBuilder, because builder does not handle AutoConfiguration properly

SimpleTaskAutoConfiguration now has an annotation AutoConfigureBefore the BatchTaskAutoConfig so that it is processed prior.  THis is so that that BatchTaskAutoConfig can create the appropriate beans

SimpleTaskAutoConfiguration has new annotations so that it is AutoConfigured after BindingServiceConfiguration and after SimpleTaskAutoConfiguration.  This is so that it does not attempt to start emitting messages before stream is ready and it can create the appropriate beans after SimpleTaskAutoConfiguration has run.

Renamed SimpleTaskConfiguration to SimpleTaskAutoConfiguration.

Task version updated to  2.1.0

Added missing headers

Updated documentation.

Deprecated EnableTask

Added ability to disable Task autoconfiguration.

Removed @EnableTask from tests

Resolves #439
Resolves #440
Resolves #448
Resolves #466

spring-cloud-task-samples/batch-events/src/test/java/io/spring/cloud/BatchEventsApplicationTests.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2016 the original author or authors.
+ *  Copyright 2016-2018 the original author or authors.
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -50,12 +50,14 @@ public class BatchEventsApplicationTests {
 			context.close();
 		}
 	}
-	
+
 	@Test
 	public void testExecution() throws Exception {
 		SpringApplication.run(JobExecutionListenerBinding.class, "--spring.main.web-environment=false");
 		SpringApplication.run(BatchEventsApplication.class, "--server.port=0",
-				"--spring.cloud.stream.bindings.output.producer.requiredGroups=testgroup");
+				"--spring.cloud.stream.bindings.output.producer.requiredGroups=testgroup",
+				"--spring.jmx.default-domain=fakedomain",
+				"--spring.main.webEnvironment=false");
 		Assert.assertTrue("The latch did not count down to zero before timeout",
 				jobExecutionLatch.await(60, TimeUnit.SECONDS));
 	}