The set name is only stored, as the SetMap is used for dereferencing.
| NodeSet (const char* c_str, unsigned line) | NodeSet | 
Parameters:
| c_str | the name of the set. | 
| line | line of configuration where node was created. | 
| DEFINE_VISITABLE () | DEFINE_VISITABLE | 
| const string&  setid () | setid | 
[const]
Returns: the name of the set.