DATACMNS-406 - Polishing.

Refactored code in RepositoryMetadata implementations to avoid compiler warnings. Some JavaDoc polishing.

Original pull request: #58.

src/test/java/org/springframework/data/repository/core/support/DefaultRepositoryMetadataUnitTests.java

@@ -88,7 +88,6 @@ public class DefaultRepositoryMetadataUnitTests {
 	public void looksUpIdClassCorrectly() throws Exception {
 
 		RepositoryMetadata metadata = new DefaultRepositoryMetadata(UserRepository.class);
-
 		assertEquals(Integer.class, metadata.getIdType());
 	}