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
@wluyima I agree that set0 has a higher weight than set3, but I did not change the sort logic only added check for retired concepts. Tests fail when sets are sorted according to weight, set0 before set3.