Output: Refactor declaration context traversal
Output: Refactor declaration context traversal

Factor new method AddDeclContextMembers out of PrintMembersAttribute.
It will need to become recursive to support LinkageSpecDecl members.

ellert/CastXML,thewtex/CastXML,iMichka/CastXML,bradking/CastXML,ellert/CastXML,thewtex/CastXML,ellert/CastXML,bradking/CastXML,CastXML/CastXML,thewtex/CastXML,iMichka/CastXML,CastXML/CastXML,bradking/CastXML,CastXML/CastXML