TRUNK-3840: Refactoring code to display retired set member

https://issues.openmrs.org/browse/TRUNK-3840

Refactored concept.jsp; removed repeated code.
Add code to ConceptSet.java to factor in retired concepts while sorting
Added unit test for new behavior

Updated concept.jsp view and ConceptFormController
Than that's fine, not to change the sort order if that is what it was initially.