Fix and clean ConceptValidatorTest
* fix failing test validate_shouldFailIfAnyNameIsAnEmptyString
had wrong assertion
* extract duplicate test setup into setUp method
* make conceptService a member and autowire it
* make concept cd4Count and weight members since they are used multiple
times
* arrange tests in arrange, act, assert way so reading is easier
* add test for when getNames() returns empty list
* fix validate_shouldFailIfTheObjectParameterIsNull
which expects an IAE but from the validator. However the call to
new BindException(null, "concept");
