Fix @since / JavaDoc / Tidy

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Additional client tests

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Get entity by using GenericType (so we can handle List<Foo> responses)

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>