Add non-parametrized message support to PayloadMatcher.

- add testcase (which used to cause compiler failure)
- remove <?> from PayloadMatcher to fix error
- add casts to FileInboundCAWRDTests to deal with backwards compatibility breakage

In some cases backwards compatibility is broken, see INT-1790 for details.

spring-integration-file/src/test/java/org/springframework/integration/file/recursive/FileInboundChannelAdapterWithRecursiveDirectoryTests.java

@@ -70,7 +70,7 @@ public class FileInboundChannelAdapterWithRecursiveDirectoryTests {
 		File childFile = new File(folder, "baz");
 		assertTrue(childFile.createNewFile());
 
-		List<Message<?>> received = Arrays.asList(files.receive(), files.receive());
+		List<Message> received = Arrays.asList((Message) files.receive(), files.receive());
 		//verify
 		assertThat(received, hasItems(hasPayload(siblingFile), hasPayload(childFile)));
 	}