Various methods in SimpleJdbcInsert prevent method chaining

[sbrannen]

The withoutTableColumnMetaDataAccess() and includeSynonymsForTableColumnMetaData() methods in SimpleJdbcInsert incorrectly declare a SimpleJdbcInsertOperations return type, which breaks method chaining when the instance is declared to be of type SimpleJdbcInsert.

They should benefit from covariant return types and declare SimpleJdbcInsert like the rest of the builder/configuration methods in SimpleJdbcInsert.