INT-3700: Fix FeedEntryMS for correct lastTime

JIRA: https://jira.spring.io/browse/INT-3700

Change to calculate proper syndicate entry date for comparison when
adding feeds for processing.

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unit test for recent changes to FeedEntryMessageSourceTests to verify
proper last seen date calculation.

updates for comments from code review

* newline at EOF on atom.xml
* removed question from code
* fetch files via classpath instead of file system
* 'else' on newline
* authorship on class

Polishing

spring-integration-feed/src/main/java/org/springframework/integration/feed/inbound/FeedEntryMessageSource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -52,6 +52,7 @@ import com.rometools.rome.feed.synd.SyndFeed;
  * @author Mario Gray
  * @author Oleg Zhurakousky
  * @author Artem Bilan
+ * @author Aaron Loes
  * @since 2.0
  */
 public class FeedEntryMessageSource extends IntegrationObjectSupport implements MessageSource<SyndEntry> {
@@ -165,8 +166,10 @@ public class FeedEntryMessageSource extends IntegrationObjectSupport implements
 		if (next == null) {
 			return null;
 		}
-		if (next.getPublishedDate() != null) {
-			this.lastTime = next.getPublishedDate().getTime();
+
+		Date lastModifiedDate = FeedEntryMessageSource.getLastModifiedDate(next);
+		if (lastModifiedDate != null) {
+			this.lastTime = lastModifiedDate.getTime();
 		}
 		else {
 			this.lastTime += 1;//NOSONAR - single poller thread