FIX tests : add prefix "api/" on rest calls !
refactor : move random string generation into TestUtil
change rest login process URL tp /api/login
allow JSON serialization for null values
add Bean Validation 1.1 supporty with Hibernate Validator
add constraints on User and UserView objects and validation with @Valid in @Controller
at this point, when the validation fails, the MethodArgumentNotValidException is thrown
add @ControllerAdvice to manage MethodArgumentNotValidException :
when a MethodArgumentNotValidException is thrown, a new ValidationErrorsView is created with all the validation errors (field and error message key from Bean Validation)
The client must display localized error messages according to the message key for each error
add Google Guava 18.0
Merge remote-tracking branch 'origin/master'