Added ObjList::setUnique() to uniquely set an object in the list. If the object is not already present in the list, it appends it to the list.
Inlined NamedList::setParam(NamedString*) which now uses ObjList::setUnique().
Only iterate once over parameter list when trying to set a parameter in a NamedList with name and value.



git-svn-id: http://yate.null.ro/svn/yate/trunk@5683 acf43c95-373e-0410-b603-e72c3f656dc1