Fix generics in ElasticsearchEntityMapper. Extract methods. Move enum conversion handling to simple type handling for symmetric implementation. Swap comparison of nullable types to avoid potential null dereference.
Rename ElasticsearchDefaultTypeMapper to DefaultElasticsearchTypeMapper. Move MapTypeAliasAccessor to DefaultElasticsearchTypeMapper.
Introduce SearchResultMapperAdapter to avoid empty method implementations in anonymous classes. Javadoc, reference docs, formatting.
Original Pull Request: #237
