code: protected boolean markOnline(Computer c) {
          if(isIgnored() || c.isOnline()) return false; // noop
          c.setTemporarilyOffline(false,null);
          return true;
      }
docs: Utility method to mark the computer online for derived classes.
  
  @return true
  if the node was actually taken online by this act (as opposed to us deciding not to do it,
  or the computer was already online.)